If you’re following the beginner course, I suggest that you use one of the schedules that Josh lays out. The bass is quite a physically demanding instrument, and it might take a while for your body to get used to playing it.
I was very excited at first, and set out to complete the entire course as quickly as possible. I practiced for hours every day, and I wound up hurting my fretting hand. I had to cut down my playing time drastically for a week or so until my hand had healed.
There are some great suggestions for how to avoid hurting yourself in this thread: Hand Care.