Easy....
Rating...thats is your WF figures. A rating of #7/8 would traditionally mean the rod is suitable for a double taper 7 or a weight forward 8 line.
Sections....2 means the rod comes in 2 pieces, 3, means three pieces etc etc. The more pieces means a shorter rod to carry in the car.
Handle.... RHW means a Regular (i think) Half Wells....normally on lighter rods. Basically the handle is tapered towards the tip for delicate casting. FW is Full Wells...ie, a parrallel handle for heavier work and all day casting...the +EH is for Extension Handle...ie, about an inch or so of cork sticking out the bottom of the handle.
So..if you where looking at say the GRXI008, its 9 and a half feet long, takes a doubel taper 6 or a weight forward 7, comes in 3 sections and has a handle designed for general casting with an extention.
As for rels...stay on the Greys website and look for a reel that matches the rods rating...I like large arbor reels..but its a personnal thing