Hey, I am not too far from you! We also left our pool uncovered over the winter. Let's just call that an experiment that will not be repeated....
Anyway, I'll tell you what we did to get started with clearing it out.
1. Run your tests. Pay attention to CYA. Ours was down to 0. Start working on your water chemistry as per the
@mknauss post above.
2. Started with the pool leaf rake. This is essential. Use it to clear all the gunk of the bottom.
3. Once you've got the leaves out and you've started with the chemistry you will likely have algae dropping on the pool floor. We had really high water levels because of the all the rain, so I was able to vacuum a lot of this to waste - to the point where I got the water level to the midway line of the skimmer.
4. From here, it's a matter of being patient and keeping your chlorine at a level that it will always be killing the algae (see your CYA/chlorine chart
Chlorine / CYA Chart - Trouble Free Pool).
5. Keep vacuuming and keep brushing. You want that algae running through your filter, not sitting on the floor/walls of the pool.
That's about the stage I'm at now. I'm pretty sure I'll have it cleared up by Memorial Day (with some patience. Good thing it is cold an no one is even thinking about swimming).
Good luck!