Firstly, you need to brush all the surfaces inside your pool to remove any sticking algae: You can then use a large leaf net to remove large debris from the water, and vacuum the pool to remove all fine particles.
Secondly, correct the pH level (7.4-7.8) first by adding pH Increaser before adding any chemical in the water.
Thirdly, shock the pool using lots of liquid chlorine to kill all the algae; depending on the number of algae in the pool, it may take 2-3 days for the pool to clear up. The filter should run 24 hours a day for faster results.
Finally, after the algae is over, balance all the chemicals starting with Free Chlorine (3 ppm) then raise TA using alkalinity Increaser to read between 80-120 ppm.
1. How to balance pH and TA: http://hubpages.com/swimming-pools/Lowering-Total-...
2. How to get rid of pool algae: http://hubpages.com/swimming-pools/clearing-up-a-g...