To assemble an AR type rifle you'll need a decent vice for the barrel blocks, the proper screwdrivers / allen wrenches, a set of pin punches, hammer, a torque wrench (in/lb and Ft/lb) and the "armorer's wrench" - special tool for the buffer tube, barrel nut, flash suppressor cut to fit on a breaker bar/torque wrench.
Depending on the exact parts used you may find snap ring pliers and a hook spanner useful.
Most of all, you need good, clear instruction, from a recognized source, not just some yammerhead on Utube….
You might find headspace gauges useful, but there is no adjustment possible, if the headspace is "off" your only real option is to replace the parts (barrel assy or bolt, or both)
There is no "milspec standard" for AR 10s. Different makers do their parts slightly differently and the only way to be reasonably certain everything will fit properly and work together is to get them from the same people.
Considering that, you might consider whether the "fun of the build" is worth the slight difference in cost between buying parts, assembled groups, or just buying a complete rifle.
