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
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.