How to build a wall is a skill that you can acquire on a moderate scale with a little bit of experience, or even some good old fashioned research on the subject. There are numerous reasons as to why this skill would be valuable to you. For example, you might need to build a wall in your home so that you can have that closet you have always wanted!
The first step when building a wall is to lay it out with pencil marks and/or chalk lines. You need to measure and square up the wall precisely where it is going to sit. Once you know exactly where your wall is going to sit, you will want to tear up whatever flooring is on the floor under your layout. If it is carpet, simply cut out the piece you will need so that the wall can sit right on the floor, and not on top of the carpet.
Once you have the immediate layout space stripped down to the wood floor, you will lay out the wall again, this time right on the floor itself. Once you do this, get your measurements and build your wall out of top plates, bottom plates, and studs. Then, stand your wall. Make sure it is level, plumb, and square. You will then want to make sure to fasten it to both the floor and ceiling, and even another wall if applicable. If the room needs to be insulated, you will need to insulate the wall, then sheet it with drywall or paneling.
How to build a good wall is a skill learned by experience. You would, however, benefit from having a good carpenter or builder help you the first time, just so that you can make sure that your wall is built right so that it won’t cause problems later!