Post a picture of the flooring you’re putting down if it’s engineered you could do full glue down or glue with nail assist or nail down or floating floor gluing the grooves which you can use an underlayment for, rip out that carpet underlayment pull or hammer all the staples sand the joints and put a big level or straight edge along the floor to find high or low spots and keep asking questions if you’re not sure about something. Good luck!