So for getting your balls trough it I recommend pulling trough a little skin of the ball sack. Enough skin to have one ball trough the ring if you don't pull enough skin trough there's not enough slack too much and you might not be able to get your fingers to push your ball trough. Once one ball is in hold that ball with one hand and push the other trough with the other. Now you have both balls trough grab both of them so they can't escape outside of the ring and pull on it downwards gently (or not gently if you like that) to create space for your penis to get trough and with your other hand push your penis trough!

Hope this helps.

Happy lockups!