1st attempt - ventilation

Hi everyone! I'm about to start my first ever grow. I have zero experience, very little knowledge and so so many questions. I will work on a diy tent 60*70*120 cm (23*27*47 inches), the tent will be in my bedroom's closet. Is my tent considered a micro one or not? I have trouble deciding what kind of ventilation I need. I can perfectly control my bedroom's temperature (is this helpful and/or has anything to do with ventilation?). Just bought my led light. It's a Kingbo series 120 actual watts full spectrum so my guess is it will provide just the right amount of heat. I'm looking for a cheap but decent solution. Do I need a whole kit or could it be just a fan? If I didn't shut the tent's roof could it be useful for ventilation or it would just be a problem/mistake? My budget is no more than 30-40p. Please help me by correcting me and giving me suggestions!!! I know there's a chance I'm asking things that have already been answered but everything still looks like a mess...
Cheers!