You can assume you don't have any chlorine in the pool since it has been green for a year. You will want to get a leaf rake and start scooping out as much junk as possible. Then add water so it covers at least your intake so you don't run the pump dry. Start the pump when you can be around to backwash it when pressure rises. At first it will probably have to be back washed twice a day. Using pool math, you should add about a gallon of 6% bleach to get your FC level to 12. This is assuming a CYA of 30. You won't really know how often to add it though without a test kit that can measure chlorine above 5 ppm, since your shock level is 12.
You can go it blind but you risk adding too much chlorine and possibly damaging equipment or adding too little and battling your pool for weeks or months longer than necessary. You'll have to decide what's worth it to you.
I just got done doing this with my pool the same as yours. It was in bad shape since last summer. It's now sparkling and took me a little over two weeks to get it there (wasn't able to dedicate as much time as needed at first).
Good luck!!!
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$24 is too much if it can only test up to 5 PPM. that won't help. Might as well get the $6 kit at walmart does the same thing. Just know it WON'T measure as high as chlorine as you need it to to effectively do the SLAM.