Vocal Booth Foam Layout

So I'm developing a vocal booth, which I've used a few times, but is quite bouncy at the moment. I recently bought a desk and got 36 square feet (in 1x1 foot squares) of auralex foam (2 inch deep) free with it. I'm also considering buying some LENRD bass traps for the corners, I have $400 max. The walls and ceiling are cedar and the floor is tile (the room was a small sauna). 1. What would you assess as the "hotspots" of this room where acoustic treatment is most needed, and could be treated using the aforementioned materials? 2. What additional materials would you recommend? (Washington, DC) I hope this fits the mold for an ideal post!