Tampons should be inserted as far as you can comfortably reach or until the applicator plunger is all the way in, once in position you should not feel any significant discomfort - if it hurts to sit or move then the tampon isn't in high enough, push in further or remove and try again in a few hours. As long as the tampon is in the vagina and used correctly you shouldn't leak.
Yes, a man would know if you have a tampon in when he inserts his fingers into your vagina. He would be able to feel the tampon inside the vagina.
You would change just as you would normally - take a tampon from your locker and go change in the bathroom. If someone was to notice it doesn't matter, people know that as a woman you menstruate and there is no shame in that what-so-ever.
I'm sure that there are videos of an actual woman inserting a tampon, but this would be a very specific type of pornography so not easy to find. If you need to see how to insert a tampon then there are many videos on YouTube explaining how to do this and using fake vagina's to show you how. Tampon use is not so complicated that you need a video to know how to do it.
how do you know if you bleed too much when your on your period
I would say as long as you have the right tools and then know how to bleed the lines after you should be fine
If you took the birth control pill correctly and consistently during the prior weeks, you're still protected during the pill free week. If you made an error, you may be at risk for pregnancy even while having withdrawal bleeding.
A TAMPON you know
Yes, you would be able to feel if there was a tampon still within your vagina. If you suspect you may still have a tampon in place clean your hands and insert fingers vaginally to feel around the vaginal canal to check - your vaginal canal isn't that long so you should be able to reach easily, but if you do struggle try to squat and push down as if you were passing a bowel movement. If you can't tell if there is a tampon there then you should tell someone to ask for help or see your doctor.
Alright, I'm going to answer this because I am extremely happy I don't have to wear pads anymore and I just efficiently used my first tampon and I want to help others. First, make sure you know where your vagina is. Get the tampon opened and ready (after you washed your hands) and you HAVE to RELAX. Take a deep breath and let it out slowly and think of something happy and calm. To be honest, I tried the one leg on the toilet seat thing but it didn't work for me. I eventually ended up on my back on the floor with my legs spread out. Start feeling around with the tampon.. I know this sounds weird, but you'll understand why once you try. If you try putting the tampon in and it just "pops" back out, you haven't found the right hole. It happened to me. So feel around and aim the tampon back towards your waist a tiny bit and there should feel like ANOTHER hole in your vagina. If you find it the tampon slides right in really easily. I really hope this helps!!
Of course it would be 'gross' to change your tampon in class, just as it would be 'gross' to go to the bathroom while you're in class. If you need to change your tampon simply let your teacher know you're going to the bathroom and go change as anyone else would. Ideally time changing your tampons so you can do it between class rather than missing your lessons.
A tampon and a pair of dark wash jeans
If you can still see the tampon once it's inserted then you've not inserted it far enougj. Remove the tampon and try again later, this time insert higher - it's best to use non-applicator tampon so you have better control over insertion.