see what products they have at your local paint store, and follow instructions on the can, and get paint store guy's advice. generally you clean the area well, remove loose paint, etch conc with muriatic,careful, the acid turns some shoes into peanut butter, use acid proof broom/scrub brush, they are cheap, rinse well. Use a latex epoxy with a small amt of sand stirred in. it takes surprisingly little sand, maybe 1/2 handful per gal., and it stays in suspension quite well. I suggest you dont use the commercial non skid additives, I've found them to clump up. plain sand works well. Depending how the first coat goes, you can usually leave the sand out of the 2nd coat.