Which image are you using?
What satellite set up do you have, fixed dish, with multiple LNB's, Motorized dish, with twin/quad LNB?
Tuner A should be setr up to the satellite you're trying to view, depending on your dish set up.
e.g. A fixed dish, with two LNB's, for 13E, and 19.2E, should be Simple, Diseqc A/B, A = 13E, B = 19.2E.
Then once Tuner A is set up, correctly, you can either set Tuner B up independently or Equal to Tuner A.
Please post back with more details, regarding your satellite set up.