I just started using tampons!!

Elle • Ellende • 17
please help me! I'm so nervous about getting tss!!!
How often should i change it, especially when i'm in school? My flow is pretty heavy so will i go through more tampons faster? Please share videos or tutorials on how to put it in, bc i it's weirds me out that i can feel it in there but it's not painful at all. Thank you so much