Enclosure design help

[Grandy]

I recently bought to RP-1500, and 2 skar evl 12s I know it's way under powered but I had it running to MA-8s and was looking for a little more bass  so I was impressed with 8s so I seen that evl were basically similar motor and basket so I thought I would give it a try I'm going to upgrade the amp when money allows but just looking to do the best I can for now... I'm looking to build a 5 cubic foot box my layout is 37 wide 24 tall the length can be anything necessary to get the write cubes It's in a 01 Mitsubishi Montero  a Clarion cz702 HU along with a Clarion EQ.. I've tried using apps on my phone to create a box but have had a hard time coming up with something that I'm sure about.. I want the subs facing up with a slot Port facing up common air between the two any help would be appreciated I'm somewhat of a noob and I don't have a computer to use the Torres system any help would be much appreciated thanks in advance.. Randy