Well ther's an Installation Guide for 1511 available at https://help.sap.com/s4hana_op_1511?current=s4hana_op_1511#section2 is that what you where looking for?
I'm sure you don't have to do a "System conversion" from ECC to get to S4 HANA if you don't want to, you can take the "New implementation" approach as well!