video to create a polished final product

How do you edit a video to create a polished final product?

Use Adobe Premiere Pro.

That's such a broad topic to answer simply, but at the least you'll need an editing software, like Adobe Premiere, or Davinci Resolve (which is free for basic functions); also you might consider using a motion graphics editor, like Adobe After Effects, for applying titles and various special effects.

Start from there and advance as you get more experience.

too many software uses every have different choice .some people use da vinci few people use premier pro.its totally you chour which software is more comfort for you