Did you ask about this when you bought the stuff? You have some serious issues there.
Rope border is challenging but can be done with the skill of an experienced tileman. If you're a rookie, good luck. If you must do it yourself, tape over the rope border and do it as a stand-alone project later after you've grouted the rest of it. You'll need a lot of time as a novice to pick the grout out of the rope texture, and if you only spread the grout in the rope area, the grout won't set too fast and get away from you.
Secondly you cannot grout the tumbled marble without getting it into the holes. Maybe this post is a troll and I'm falling for it, but you've got to just smear that grout all over, and wash it off like usual.
Thirdly, you better seal that tumbled marble first or you may have a heck of a time getting the grout off the surface.
I'd re-think that "dark" grout color if I were you. If you want to bring out the beauty of that tumbled marble in the end, it's always best to match the grout as close as possible to the marble. This makes the grout appear in "the background" when finished, and the beauty of the natural stone is the dominant thing. Also, as you grout into the holes in the marble, you'll still see the areas where the holes were, letting the "old world" look of the tumbled marble be there, but the holes won't stand out. If you like the holes, just "wash out" a bit more as you sponge the grout in the middle of the tiles to dig out the hole's some. If you grout with a dark grout, you'll make the grid of dark grout the dominant thing in the end, and the holes will look awful.....the beauty of the tile will be relegated to the background.
Grouting can make or break a job so if you don't think you can do a GOOD job at this point, hire an expert to finish it.
thetiler