How do you install age of mytholog expasion without age of mythology full installation

Impossible. You need the original Age of Mythology before installing the expansion. That's why it's called expansion. It expands the original version. There's also a gold version of the game, but that's just the original version and the titans version brought together on two disks. If you install gold, you will actually still be installing original version and the expansion, so it won't make any difference. There is a trial version of the titans expansion. For the trial version, you don't have to install original first, but I don't think you want a trial, you probably want the full game.