I see so often jumper do stacks and it looks very easy, but when iam trying it i glide down at 90 percent

When a stack works is it an very easy one or i have luck only -> i must do something wrong !
It would be great if somebody have a heart for stacksuckers like me and build a little stack-tutorial (with video would be nice) like the many strafejumpstutorials.
Thx afore
