What Rob just said. Additionally cleaning. You really should clean everything before you start assembly, though I don't always follow my advice. As to ease, check the sites that are more specific to your interest. Most have reviews of new releases and you'll get an idea of hte ease or difficulty of the kit. Even some of the major companies, okay, at least one of the major companies now affiliated with one of the major online shops in the US has sometimes strange ideas. I reviewed a couple buildings by one of their subsidiaries. Some parts were beautifully detailed on both sides, others were poured into one sided molds making clean up a potential nightmare.
You're also likely to hear that resin dust is a nearly poisonous substance and you'll need a super respirator to wear while sanding it. The fact is, resin dust, like any fine dust is an inert irritant. You shuld take the same precautions sanding that as you would any other substance, such as wood or plastic.
Fact is, though, you'll find things in resin you'll neer find in plastic.