First, this is a 1/1 row + 1/1 row. This can be done manually or if you have a page builder like visual composer, or a page builder in your theme.
What you need to do is setup a new gallery and in the Navigation Style, set it to none, because we will have no navigation inside the gallery but it will be outside. That said, we need to link to the outside gallery. Scroll down to Outer Parts and set Second Con, Outer Navigation and Outer Navigation, Show Video Author to On.
You just need this code setup in a TEXT box or
In the right 1/3 container enter
Of course, if you don’t have a page builder, just pasting those two in a TEXT default wordpress editor will work.
Also there are some extra options you can edit in the extra classes box for styling.
Go to video gallery you are editing, scroll to Design Options and you will find the field Extra Classes.
You can input here something like
try-breakout -> tries to make the main video fullwidth even if it not.
try-height-as-window-minus-offset -> tries to make the main video fullwidth even if it not.