Welcome to the forum.
What type of build did you have in mind? Some folks consider a "build" finishing a preassembled, in-the-white gun that only needs sanding, stain, and stock and metal finishing.
On the other extreme, others consider building from a squared blank, buying custom components that fit that particular style of gun and filing and fitting each separate component to larger assemblies.
In the middle of those extremes, is a variety of parts kits utilizing a 90% pre-inlet and shaped stock.
Each of those builds requires certain skills and tooling to complete. The more involved a build, more skills and more tools are required.
It all depends on what you consider a "build."
God Bless,
J.D.