adding audio to video

I have arranged some music for a video and have everything the way i want it.

how do i resave the the video, embedding the audio track that i’ve created.

I know this is simple for most of you but up to now i’ve just used Nuendo to produce music.

https://www.steinberg.net/forums/viewtopic.php?p=840313#p840313

https://www.steinberg.net/forums/viewtopic.php?f=276&t=121411