Can you create sub-sites inside of sub-sites in Sharepoint? First off, how do you create a sub-site? How do you link a sub-site to a main site?

I am creating a SharePoint for my organization. I am new to sharepoint overall, and I believe I need to make a Site with multiple sub-sites. The idea is that these sub-sites would also have sub-sites until you get to the team you desire, and documents would be uploaded into there (image attached).

-How do I create a sub-site? -How do I link my sub-site into my main site? -Is this even possible? Structure of Sharepoint