We set up our HBAC nest in our bedroom with a rented pool. We ran a hose from the bathtub to fill it and laid towels and rugs on the path from tub to bathroom. We put old sheets on our bed on top of a mattress pad and garbage bag. It was overkill because there was actually very little mess. We didn't do much for ambience, just lit one candle. I was so in my own head, it barely mattered, but it was comforting and calming to be home. Birthed in the tub and then blissfully crawled in bed with my baby boy.
P.S. I don't recommend filling the pool this high. It was too deep for me to feel stable, I was too floaty and I had to hoist myself up to nurse in the tub. Sit in the tub before you are due and mark a line a bit below armpit height while seated flat.