I am putting the hardwood floor in myself in my basement. Should I install the door jambs and doors first, or should I put the hardwood floor first?

If you can keep from scaring the floor, when installing the doors, I would opt for floor first. Getting under, undercut doorjambs can be frustrating.

I wouldn't put hardwood in my basement. Unless it is and engineered hardwood, the mill it was produced at (any mill( does not recommend solid wood in a below grade application.

Just be aware that if you set the door frame on top of the floor there will be a 3/4" gap between the door slab and floor. Prehung interior door units are made to receive carpeting without cutting the bottoms off of door slabs. Should not be a real concern in a basement.

Thanks Jerry and Floor Guy. Yes it is a basement but my home sits on a hill. From the front of the home you cannot see the basement. The basement can be seen from the back yard. From this view it looks like a 3 story home. Also the basement has a wood floor and sits 4 feet off the dirt. I think I will be alright with the 15# roofing felt under the bamboo flooring and the plastic over the dirt under the basement floor. Good job looking out for me.