How to change the spring preload on ninja 500?

how to change the spring preload on ninja 500 its to low . needs to be higherHow to change the spring preload on ninja 500?
Its a process of diffrent steps, please note though, you do not change the spring tension to make the bike sit higher..it will handle like crap. go to google and look up ';Setting Race Sag on street motorcycles'; It doesnt matter what bike it shows you how to do it on, the process is the same for all and a little bit too long for me to type it up on here. You will need 2 people to do i though, you sitting on the bike and another doing the measuring.