I had never grouted tile before this. I will admit that I heard all of the horror stories. It is worse than dry wall - definitely NOT true! It takes forever to get the floor clean - this one had me worried because it was not too difficult. I did watch a couple of videos on YouTube. This one in particular was most helpful. In the end there was nothing to do except jump in and actually do it.
The floor before. I vacuumed it well and then mopped over it.
W spread the grout all over the floor taking special care to fill the joints.
I do not have pictures of the next step simple because I was busy cleaning up the floor. It was completely covered so that it looked black. I took care to wring out the sponge until it was just damp. I wiped in circular motions taking care not to use too much pressure.
I then left the floor to dry for a couple of hours. You can see the haze that was left on the tile. That was cleaned up by going back over the tile with a damp sponge using a bit more pressure this time. Yes, it was hard work. I was down on my hands and knees cleaning the floor. (Buy good knee pads!) In the end it was over and done though rather than lingering on and on like the dry wall did.
We opted to do only a few rooms at a time. It usually took about half a day for each grouting session. We worked on lighter jobs the rest of the time. I do not expect grouting tile will ever by my favorite way to spend an afternoon, but it is preferable to dry wall.