If you want to learn as you work, buy one of the Systemas. (When you look it over, you will see that you have a major challenge.) Then, buy a good quality match barrel, a good quality trigger, extractor, long ejector, slide lock, disconnector and recoil system. You should also buy a set of good quality fixed sights.
When you get an aftermarket grip safety fitted and flare out the mag well, it is time to buy some Wilson magazines and head out for the range. When you fire it for the first time, you may realize that you need to replace more parts. Do it!
If you want to be a pistolsmith, you will have to be able to outshoot everyone on the firing line...and that will take some practice. If you can't shoot one, you won't know whether you have done an acceptable job building it.
Accomplish that and you can look at yourself in the morror and say you are a pistolsmith. It might take a decade or more before others will say that about you, but if you apply yourself, it will happen. And, you will have your very own X ring shooter to show others on the range.