If you're not familiar with this process, even with some 'advice', it's a dangerous and potentially costly job to do.
The best advice I can give you is to hire an Excavation Contractor. Once the basement is dug and pinned, conceivably you can 'do the rest'. Otherwise, you'll be asking 'us' for advice on how to explain to your insurance company why the 1st floor is now part of the basement.
I'm sorry but that's the best I can do. My best to ya and hope this helps.
Jay J -Moderator
PS: There are times where hiring a Pro is the best and right 'advice'. IMO, this is one of them ...