building bikes is bery easy if you know how do it
a few suggestions
grease everything nuts bolts chain bearings freewheel hubs
use the right size wrench or socket allen wrench adjusting arm wrenchs are very nice when making a custom bike with diffrent size nuts and bolts switching sockets can start to get annoying
try not to strip anything
use the right size parts
dont over tighten spinning parts
fill tires to max psi
if using axle pegs that are threaded put them on first then nut to be sure they arent going to come lose
and i hope some this helps good luck and have fun with it