It's all a learning game brother. I see you use fabric pots. If the pot feels wet/cold one the outside there is still enough water in the pot. As soon as it get's dry give it a watering. Don't overdo it and stay close to the seedlings.
Below 20°C/68°F plant growth slow down, so try to stay around 25 á 27°C/77 á 81°F is the optimal temperature, but a couple of degrees in either direction don't do that much harm

Try to keep the humidity between 60 and 70%. In the beginning you can go to almost 100%, but you're past that point anyways.
Lights... Keep 'm as close as you can. If you keep your hands under the light at the position your plants are going to be and it feels to hot then it's to hot for your plants as well.
Good luck and keep sharing the pictures. We like picture