Easiest way to set up traps is to find a trap cache. They are pretty common, mostly 8-9 beartraps, 4-5 crossbow traps and about the same number of shotgun traps.
They usually have a few goodies at the heart of them too.
By the way, I wouldn’t even try disarming beartraps without a traps skill of 1. Crossbow traps are a tad harder.
Thankfully these two traps don’t do that much damage-- i.e, if you mess up the first time you’ll still have all your limbs attached.
Easiest traps to make by hand are beartraps, you need a wrench then go explore some craters or dissasemble things like lawnmowers and such for springs. 3 scrap metal later and voila, you’ve got something that can stop a hulk dead. You’ll need more than one, though.
[spoiler=Protip]Don’t mess with shotgun traps or landmines.
Ever.
And wear a goddamn helmet.[/spoiler]