There are some really good maps people make, and I'd like to enjoy them in single player, but I have no idea how to save a map and click on it as a custom map/template (not sure what its called) how can I go about doing this?

Under the Single Player tab, click the green "Custom Game" button and then select "Custom Game" on the next screen as well.

This will take you to the "Configure Settings" page. Under the "Maps" tab, you can browse through the different maps or search for one by name. Alternately, you can add a map to your favorites list, the button for which can be found on the ride side of each map's individual page.

That should say "right side" not "ride side".