They glue together with CA glue.Only use acrylic paint and washes as enamels could cause them to stiffen and break.It happened with one of my builds.The ones I did with acrylics about five,have been fine.Many have said that they have found them bad in the box or that they fall apart on their own,that hasn’t happened to me.You may want to invest in AM tracks if you can afford them.There are many options,plastic links,resin links,or metal links.All are nice,but they do add a cost to your build,at least $25-45 dollars.So it depends on your budget.