Beginner!? This is some pretty good advice for a beginner, some one has done their home work.:clap2:phosphorous is an element, phosphate (ie monopotassium phosphate as a fertilizer) is a salt containing phosphorous.
phosphates are *not* bad in the planted aquarium, in reasonable amounts in proper ratios etc.
limiting amounts of phosphate in a planted aquarium *can be bad*, as plant uptake can stall. So a proper amount of phosphate in the water column is good for a planted tank.
how much phosphate is dependent on your goal. Check out PPS / EI strategies for info on how much phosphate you want to add to your aquarium.