Vico maintains a list of locations while you move around in files. Some movement commands are considered "jumps", and those jumps are remembered in a list.
Generally, movement commands that generate jumps are those that move more than a few lines. So the word, character and line search motion commands do not generate a jump, but the line and search motions do.
You navigate the jumplist either by pressing the jumplist arrows in the toolbar, or pressing ctrl-o to go back and ctrl-i (or tab) to go forward.
Only the last 100 jumps are remembered, and duplicates are removed.