How to merge video and audio?

Question

Video processing

Hey!
In general, I bought a subscription in one private site with tutorials for one video game. I downloaded all the content from there, but they made such protection there, I don’t rummage in editing.
Video without audio track is in .webm format , and audio track is in .mp4 format . The question is simple: what program should I use to glue them together and do it right?)
Thank you.

Answer 1

Can be assembled into one container via mkvtoolnix GUI.

Answer 2

Sony Vegas insert 2 tracks and render. Profit.