tap on SOURCES
press on add in the top corner
click on the add button and Input http://www.blackra1n.com as the source address then press the Add Source button. Once Cydia has added the source press the large Return to Cydia button.
after its done..
select the blackra1n option in the sources winidow and
let the iphone do the installation.
complete the installation. let iphone restart or do its work.. if required restart
mail me at email@example.com for more information