We have recently purchased this house and are replacing light fixtures which have pull strings to turn them in. I want to install a combination switch to a new fixture but I am not sure if this will be possible. I have 1 wire which is bringing power to that area. I am confused as to the best wiring diagram to be able to use the outlet anytime and the switch turn the light on and off as it should be doing. The instructions with the Leviton switch are simply for the experienced and that I am not. Your assistance will be greatly appreciated.

If it is pull chain controlled now, it may not have a switched leg, if wiring is done with conduit, you could pull or push an extra wire to allow it to be switched. If Romex, you may be able to switch light and receptacle together, if it is OK for you.
As far as wiring the switch/recepticle: one side of combo will be for your hot and will have a jumper connecting receptacle hot and switch hot.
Other side should have white screw for receptacle neutral, the screw on the other side of the switch half goes to light hot.