Returns you can do over the top, that link is the durso, pretty simple, as you can see in the picture the pipe size is larger than the bulkhead, like 3/4 to 1". you need a T, a 90 (forget what it's called, has a female on one end and male on the other) and a cap then just follow the picture. Look at the height and try a few different heights before you glue or don't glue at all