Your set up is 100 times better than mine, I still don't have a tent, remember one of the most important things to have in a tent is air flow, your going to need a small extractor fan, depending on what size holes the tent has get a little fan accordingly, you only need a extractor for now, that will create a vacuum inside the tent...
You put the little fan in one of the holes, I'd suggest one thats either high up or on top, if you don't have any, one on the bottom will suffice, place the little fan snugged inside the hole to blow air out of the tent, and leave the hole you have in the bottom open, that will create the airflow you need to keep the plants breathing...
Make sure light doesn't leak in during the dark cycle, if your going to have the lights on in that room then, zip yourself up in the tent with the grow light off and and the room light on, and see if any light leaks in. If it does, take up the leaks.