You can book an instructed session for your kids, where a Boulders instructor will supervise the session.
You can also bring your kids and supervise them yourself, either bouldering or rope climbing.
To take them rope climbing, you do need to know how to belay, how to fit a harness, and how to tie a figure of 8 knot. If you don’t know how to do this, you will need to book an instructor.
If you want to take them bouldering, you can do this even with no experience!