BIGOH, welcome to the forum (uh... you've been here as long as Matt and I, so let's try - WELCOME TO POSTING!! )
Here's a link to doing the Hayward gaskets (and a link within a link to another discussion of the process) https://poolforum.com/pf2/showthread.php?t=6232. Don't worry too much about brand on the 'how to', they all work ~ the same (as long as it's a 6 position multiport and not a 'push/ pull' type) - but you do want to get the right replacement parts, so be sure that they match up properly.

If you need any more help/ advice/ tips - just ask!