Firstly track down a copy of Authorisations Made Easy and read it.
Secondly get training. This is basic stuff and <i>if you can't do this, you shouldn't be put in a position where you have to maintain the security of a company.</i>
Thirdly, this is what you need to do:
Run profile generator, tx PFCG
In the role name field, enter the name of your role and click on the the change button (pencil icon)
Click on the Authorizations tab and click on the change button. This will take you into the authorisation maintenance.
Scroll down the list of objects until you find object F_LFA1_AEN (F_LAF1_AEN does not exist)
Click into the auth object and in the Field Group field, enter 1
Generate role using generate icon at top of screen
