4 month olds won’t nap

So my twin girls are 4 months old and decided that they don’t nap anymore. I want to get things done around the house, but they are only down 10 minutes at a time. I’m sure they are tired, but they won’t stay asleep. What do you guys do to enforce nap time or get your babies on a schedule? What happens when the babies are off schedule? Should I let them cry a little? Thanks!!