fossil init repo; make a new fossil repository
fossil open repo; open a fossil repository somewhere
fossil add file; note: very different than git add. in fact I was very confused by git add, in fossil the repository knows what files are managed by it and there is no staging area. so you only use "fossil add" when adding a new file. If you move a file use "fossil mv" to let fossil know what you did. Along with "rm" when you remove a file. The staging area still feels like an unnecessary added bit of friction.
fossil commit
There are others I use often "merge", "sync", "revert" but they tend do what the command appears to do. Speaking of revert, the git equivalent is really strange , even among the rest of the strange git ui. Shit! I messed something up and want to revert back to the last committed change, easy, just run the command "git reset --hard HEAD"