Practice taking turns and sharing, and describe a friendly way to ask for a turn.
Taking turns and sharing let everyone get a chance to play or use something. It can feel hard to wait, but waiting your turn is fair to everyone.
You can practice taking turns just like you practice anything else. It gets easier with practice.
Mastery looks like: They can ask for a turn appropriately, or wait for one, at least some of the time without a reminder.
Common stumbles: Grabbing instead of asking, or getting upset while waiting, is completely normal and just needs continued practice.