It is very easy to build a rifle at your house with the components available today. Pick an action that accepts pre fit barrels. The popular actions are bighorn origin, bighorn tl3, impact 737R, lone peak fusion, terminus zeus. There are tons more such as American rifle company, defiance and many many more. You can go onto patriot valleys website and select their prefit barrels and they have a drop down menu that will show all the actions they make prefit barrels for.
To clarify since it sounds like you are new to this. A prefit barrel and action are held to tight consistent tolerances unlike actions of the past. Basically each action is exactly the same (close enough) since each action (of the same make and model) are the exact same barrel makers can make a barrel without having to actually have the action to fit it. Old actions have lots of variation so you had to have a gunsmith build your rifle.
So now you select the action that accepts prefits, fits your budget, has the features you like, and like the look of. All actions are going to shoot just as accurately as another basically.
Now pick a company that sells prefits that you like the price, the company or what ever other reason you pick them over others. Companies like proof research, patriot valley, preffered barrels, Fischer T&C, TS customs and many many more.
Select the contour (thickness of the barrel), select the twist rate that’s appropriate for the bullets you want to shoot, options like threaded barrel, fluting, and cerakote. Not all companies offer fluting, I know preffered barrels does but have never used them.
Now once you have the action and the barrel you use the vise I posted or similar. Clamp the barrel into it mounted securely onto a strong bench, put a little anti seize on the thread and screw the action onto the barrel. It is just a big bolt, righty tighty lefty loosy. Now use the action wrench into the action where the bolt goes and a torque wrench and tighten the action onto the barrel to what ever torque the barrel maker recommends.
Hopefully this all makes sense, if you have more questions just ask. Also watch some YouTube videos but it is seriously so easy a cave man could do it.