Open Drive and upload files into the current folder. Large files are handled with a resumable, multi-part upload behind the scenes, so big documents transfer reliably. Per-file size limits apply.
Create nested folders to structure your files however your team works, and move or copy items between folders as things evolve. A clear folder structure pays off later, because sharing and permissions can be applied at the folder level and inherited by everything inside.
Two views help you get back to what you were doing: