How do I get more heros or get my hero to become idle again on the mergical island offshoot?

They really need to document the whole island MUCH better. I have no idea how to get an additional hero (other than buying one) but to make them free again simply find them on the island or boat, click on the picture until you get to the place where it has a big green check mark. Click one more time and now the check is removed and they are free. If you go back to the mainland you’ll see them walking a run til you place them again.