How do you train to get your leg up?

Question:

How do you train to get your leg up?

What i mean is, how do you learn to do the splits and get your leg up straight next to your head from standing and how long does it take to train your body to do it?

Best Answer - Chosen by Asker: side split stretches:
1st stretch:take a thick book and put it down on the ground then put one of your feet on it and go down into the splits position as far as u can and hold it there for like 2 minutes and switch legs.then do it without the book.
2nd stretch:put one leg straight in front and the other leg fully bended and try to touch your foot that is straight and hold it for like 1 min then switch legs.
3rd stretch do the splits as far as u can down and hold it for 1 or 2 mins and switch legs.
4th stretch:if u can do the splits then hold your front foot for 30sec-1min then sit straight and bend your back and extend your arms backwards and do it with the other leg.
5th stretch: do lunges

middle splits:
stretch:do it as far down as u can and hold it there for 1 or 2min and rest for a few minutes and do it again.

high kick:
1st stretch:put your foot on the wall or a bar and face your foot/leg and reach to your foot then move your body to the side still have your foot/leg on the bar/wall and reach you hand that is farther from your leg/foot to your foot and switch legs

2nd stretch:put your hand on something strong or a bar and kick your leg (high kick) up as high as u can about 10 times then switch legs

im sorry some of these are confusing but im trying my best

and also yoga would help