doubt on upgrade of oracle 10.2.0.5 to 11.2.0.4

Dear All ,

Recently i had upgraded oracle patch from 10.2.0.4 to 10.2.05 , now my oracle version is 10.2.0.5 , now i want to upgrade oracle from 10.2.0.5 to 11.2.0.4 ,but i have a doubt from where i need to start DBUA tool for  upgrade 11 G , whether i need to install oracle 11 G or i need to start from 10.2.0.5 , if its 10.2.0.5 then how can i run.

Waiting for your need full reply

Thanks

Arpit