Here I’ve added two videos using the column block of two columns (50/50). Then added a youtube video block into left and right. Steps:

1. Click the + sign and type to search/select columns block
2. Select 50 / 50
3. Press + in first column
4. Search for / select youtube block (or Vimeo is exactly the same)
5. Paste in URL for video on Youtube (best to put videos on youtube/vimeo for all the conversions these services do).
6. Repeat for other column.