welcome to GoY,
Is this one a thermostatically controlled one so the temp starts and stops when it gets to temp?
if it is then during the day prop the lid open to let air circulate. remember to close it on the evening.

if it has a fixed temp all the time then turn it off during the day when room/greenhouse is warm, you can prop the lid open again. as the temp falls turn it back on and put the lid on.

hope this helps.
don't be afraid to ask questions. there are lots of us on here happy to help.

I had one and a lot of my seedlings failed I was told on GOY to never put lids on I tend to agree as they sweat I had so much damping off or non germination. The consensus here seems to be if it's the right time of year they should just come up in a non heated/non lid greenhouse these can get pretty cold at night . I never used mine heated as there is no thermostat on these so you get full heat . I used mine on the kitchen windowsill. I would have only used heat like in Jan/Feb when it's much colder for seeds that need to be germanated early because of our short season stuff like rudebekia , cleome, annuals need early sowing or you will be too late.

I have a heated one without a thermostat. It has vents at the top with sliding shutters. You can open these in the daytime and close them to keep the heat in at night. You aim for a gently humid atmosphere, not a wet one. You can remove the lid altogether during the day when its time to introduce them to room atmosphere. I've never lost any seedlings with this method.

my vents never opened which is why I prop them open. I rarely loose seedlings except to a vole grr little beggar!

After germination, most seeds I start benefit from growing in a slightly colder environment, so I take the lid off.