Need some help with a Formula

[Monday]

I am a very basic excel user and need some help.

I need to add this formula, =IF(E11>=6,E11-0.5,E11) to this one, =IF(IF((OR(D11="",C11="")),0,IF((D11<C11),((D11-C11)*24)+24,(D11-C11)*24))=0,"",IF((OR(D11="",C11="")),0,IF((D11<C11),((D11-C11)*24)+24,(D11-C11)*24)))

Can someone please help.
Thanks, <?xml:namespace prefix = o ns = "urn:schemas-microsoft-comfficeffice" /><o></o>

 

[Monday]

I need to add this formula, =IF(E11>=6,E11-0.5,E11) to this one, =IF(IF((OR(D11="",C11="")),0,IF((D11<C11),((D11-C11)*24)+24,(D11-C11)*24))=0,"",IF((OR(D11="",C11="")),0,IF((D11<C11),((D11-C11)*24)+24,(D11-C11)*24)))