The way you are going to do a kickflip is, for starters knowing how to do an
Ollie. After you do know how to do an Ollie you're going to want to make sure your board has enough room to rotate without hitting the ground and bouncing back up on you.
Aside from that, it's very important you want to kick out and kick to your right. Some people have a problem and end up doing heelflips. Some people find heelflips easier so they end up doing them first. It's really up to you. It's all about your preference. So do what you're more comfortable with.
If you prefer heel-flips go do the heelflips. If you prefer kickflips go for kickflips. Now some people like to take a little marker or key and scratch the edge of the board so they know where to direct their foot as they do the trick. I find that it helps a lot of people that I've taught how to do kickflips in the past.
You're going to want to kick out, just touch a little bit of the nose, slide your foot out to the edge. and make sure that it gets out but not too far out. Once it begins to rotate, you're going to want to catch it directly over the bolt. If you're lucky and you're a good skater you kind of grab it in mid-air and have your feet on the bolt before you even hit the ground.
Some people have problems with this trick because the board tends to get away from them, over rotate or under rotate. You might want to take some time to do this. You can hold onto a fence or have a buddy help you out. Some people even like to hold on of a friend's hand and have them kick the board from underneath them so that way they can get the experience of a kickflip before they even know how to do one.
If you're having trouble with this trick, try and watch some more instructional videos to get an idea how to dig your Ollie down solid, and then you might be able to move on towards your kickflip.