If this is the reel/s first servicing, I would recommend that the reels be serviced by a professional, but if you must DIY. I would recommend that you have each reel/s schematic/s in front of you before you even start.
The thumb screw on the top is to open and remove the palming side plate, and spool.
Remove the crank assembly, then there are 2 screws on the outside of the crank side cover, and, one pan-head screw on the inside of the spool race that also holds the crank side plate on. Remove those 3 screws and the crank side cover will lift off.
Good Luck & Tight Lines!!
I tear down my Revo S-L's myself. II learned this the hard way...When you open the crank side cover be cautious of the two small springs that just sit atop small posts. I always remove them immediatly and set them aside while I do the servicing.