Also what is the best brand or country of origin for ak 47.
Depends on what you're looking for and your budget. Most folks would say Russia and get a Saiga. You can convert it to use AK mags and look more like an AK or buy it converted. Nothing wrong in getting a WASR like in the video, it works too.
The biggest issue with assembling an AR isn't so much getting the parts together right - it's getting the right parts together.
US Army 1966-69, VFW Life Member, Retired Geek