This is a really useful phrase to use in spoken English. You will hear it a lot in movies and real spoken English. If you have a lot of “time on your hands” it means that you have a lot of free time.
Here is a useful example sentence to get the idea of how to use the phrase:
I quit work about a month ago. I’ve got so much time on my hands now. I think I need to start doing something useful like learning a new language or learning how to play a musical instrument. I’m a bit embarrassed to admit it, but all I’ve done in the past month is lie on the couch and watch TV.
I hope you enjoyed that lesson! I am sure it will be helpful for you. In today's world, it's important to sound great when you speak English with native speakers. Click on the link for an amazing program to Learn a REAL American Accent