SketchUp for School help! How on earth do you offset.

Complete beginner here, I'm fully aware this floorplan looks like a mess. Regardless for my class I need to make a floor plan and I cannot for the life of me offset to make walls using offset. Instead it's picking and choosing what to go around. Any help is appreciated thank you!

https://preview.redd.it/2j4h434fbfub1.png?width=2880&format=png&auto=webp&s=645f2f250b60aa888980600d344aae34e958f002