Beast feed and pump help

My son is about a week old now and I’ve exclusively been breastfeeding and it’s been going really well. I’d like to start pumping some, however, so my husband can start helping with some of the night time feedings. He cluster feeds a lot at night and I’m finding it impossible to get any sleep so it would be helpful if we could work in shifts.

I’m not sure where to start. How often should I pump and for how long if I still plan to breastfeed? I don’t want to mess with my supply too much or rush it. Any suggestions?