Have reasonable expectations. If you have two toddlers, a squirrelly preschooler, and a 1st grader, perhaps a full Rosary is too much for their attention span. Try a decade instead (or just start with praying each of the prayers one time).
Do you have a regular drive that’s at least 20 minutes long? That’s just enough time to pray a Rosary and you have a captive audience. Use this time well!
Start by teaching your very young children the three basic prayers: the Our Father, Hail Mary, and Glory Be. It’s amazing how easily most young children can memorize things like that.
It’s nice to pray it together while you’re all kneeling around your prayer table, but probably much more practical to do it while you’re walking, driving, or snuggling in a comfy chair. I found that waiting for perfect conditions rarely happens, so we just started praying wherever we were. It’s much more likely to happen that way!