Railing is a snap as soon as you get it working. There are two processes. First, you have to get it off the metal sprue. I use a #16 blade Xacto or - if I can get at them - a pair of mini-scissors. The trick is to put on your strongest reading glasses and find the points where the rails connect to the metal sprue and push your blade straight down on them - don't try to saw them off by moving the knife backwards and forwards. The standard #11 blade works too - just use it at the right angle and push down right on the connecting point - it'll cut right through. If using knives with PE I change blades often - actually I change blades often anyway - amazing how much better a new blade works than an older one even if you use a sharpening stone. #11 blades are available for about $12 per 100 blades.
You want to be using a very hard surface to work with PE. Glass is good, so is very hard plexiglass. I use black plexiglass because it's so much easier to see the parts when they come off and it's also easier to see the very small connecting points between the PE parts and the PE sprues.
Once you've got a section of railing off, I'd cut it into pieces - 2" max. Here again, you want to take your blade and push straight down on the line where you want to make the cut - never pull the blade back and forth. If you have good modeling scissors they work very well - just be careful. (I should have told you to buy extra railings - Lord knows how many I have. You don't want to worry about having enough and you want to be able to scrap a piece that gets bent. Delicate PE like WEM is very hard to repair, although it's possible with tweezers and good reading glasses.) For attaching the railing you can't do better than Aleene's Tacky Glue. This stuff is a must (it's also the US version of the stuff used by ubermeister Jim Baumann on Model Warship) because it's got something in it that makes it grab the part. Normal white glue actually doesn't work very well. Aleene's is widely available - any craft store, fabric store and a lot of hardware stores have it. Cheap and works great. I like regular but it comes in "Extra Tacky" and "Fast Drying." If you're using small links of railing they'll stick easy - but just a little glue on the bottom of the rail on some small blobs on the model - glue hits glue. Railing is thin enough that you can carefully bend into the slight curve needed for most of the deck. If you want to try a more serious curve or even an angle get a mouse pad and gently roll a paint brush handle or pencil across the piece to create a smooth curve. An angle is done on a mouse pad too - but you'd push down in the middle of a piece to create a V shape. In general, I keep railing as simple as possible. Better to put on more small pieces than try to shape larger ones. You can use the angle bend for the bow, but I'd recommend simply putting a strip of railing starting at the bow on each side - they should touch or almost so. A little bit of Aleene's in the middle or a very thin piece of plastic sprue (or brass tube if it's around) can be stuck at the tip of the bow if the railings don't meet right. If you doing a piece of the super structure I would not try complicated bends - again, just cut small pieces and put them in one by one - it's actually quite fast. Once the railing has been "grabbed" by the glue you might want to put a really small bit of CA on to strengthen the fit. My favorite CA applicator is a Xacto knife with a #11 blade that's dedicated to CA work. I put the blade through a little puddle of CA, putting the glue on the knife blade, not the tip - then apply the glue like you were cutting along the side. Less is better.
You want PE at least primed before putting it on. PE does not take to paint well. I craze the stuff with really strong hardware store lacquer thinner (the kind I wouldn't think of using with paints or in an airbrush) or you could even very carefully scratch it up a little with a sanding stone or sand paper. Prime it with what you want - get the primer on, but the least amount needed to cover. Then paint then the appropriate color - again less is better because too much paint can clog up the PE and kind of ruin the effect. It's no trouble to touch up after you're finished, but it's very hard to paint installed railings.
If you're having trouble and you're getting the railings off the sprue cleanly, I'd guess you're using too large a piece. It's also good to handle the stuff with tweezers (I have some good ones, and don't regret the money spent, and Squadron quality work okay) and remember that if you push down on railing with your thumb or anything else they'll collapse. If you're using 1/.600 scale that's probably WEM. They're very good but a little delicate. At a different scale I'd like for something a little tougher like Eduard or Empire - at 1/350 Verlinden sells cheap railings that is almost unbreakable, even if it's a little too thick. But you can do it with WEM - just remember to push directly down on the connection points to separate the piece (never move the knife back and forth) and don't put downward pressure on them - you can very easily tease a slight curve along the deck with your fingers, just use them a little like chop sticks and put the pressure along the sides and bottom of the railing - never up to down.
I had trouble with my first one. After you get the hang of it, you'll be able to rail a ship in an hour. Generic railings usually come with ladders - those are very neat if you get them right. There are instructions on YouTube for ladders - just skip the bit about turning the rungs to an angle. They also have one hand ladders for going up the side of funnels etc. You can use those for railing the superstructure, or putting something around gun tubs - it's not perfect realism but better than nothing.
Trust me, if I could do this so can anyone. Ships are terrific models, but railing and rigging are a price you have to pay to build a good model ship. If you get into them, you can start using elaborate PE, scratch building and begin to look down on airplane modelers.
Eric