How to set up different time on clock for players?

It's not an option currently.

Thank you for telling me

wouldn't it work if you play them unrated?

Yes. This should be a thing in unrated!!! Pronto Me and my way lower rated friend would like to play some unrated matches like this..

Although I'm sure some are aware of this and just want an alternative (like me), for anyone who doesn't know, when setting up a match with a friend you can click "Standard" and switch it to "Custom Position / Odds" to allow playing with imbalanced positions/material (the higher rated player would be missing one rook for example at the start), as a form of balancing games against lower rated friends.

I put in a suggestion for time odds as well because I would love that option, but just mentioning this is an option in the meantime for anyone who's not aware.

How?! I've never noticed it...

lichess has it, the button that has the plus symbol adds 15 secs to your opponent

Chess.com has that too but you may have to be friends with the member to use it.

man

how do you do it

If you're playing a friend who's weaker, you can do it by honours system. Start with 10min both, when your time hits 7.00, you lost. Basically meaning you had 3min.