I can grab rim on a 10 foot goal. I am 5’10" and have a reach of about 7’6". Please help me dunk!
Ok! Go get a large sturdy box and put it near the rim, run towards it then jump off of it and you should be able to slam no probs!
Seriously though, you want a verticle program or something right? What you should do first before anyone bothers to post here, is to use the search function and look up things like jumping, plyometrics, and explosive med ball and explosive lifts etc. Once you have spent a few days reading the threads on this, come back here an say you are sorry for not reading the posts in the first place. 
If you already have a program you are using, post it here and we will make comments. There is a lot of help available here, but what you need has already been written about at lenth elsewhere. If you have any questions on the search funtion let me know. Happy searching!!! 