That's one DIY job I have not done before is tile work and grouting, I know how to do it from observation and reading but never attempted it nor had the opportunity to try my hand at it...
...
This was a tile backsplash and only 18sq.ft. two by four inch subway tiles that come in a 12 inch square sheet with 1/8" spacing. Not a fiberglass mat, they are connected together with weird little epoxy boogers. Had to remove all the electric outlets & switches and tuck the wires back in the wall so I could cut the tile to fit around them and dry fit everything. That's where the fun started. I've done a couple of floors with just the score & snapper tool and they came out great. These small porcelain tiles break very easily and there were lots of small odd cuts to be made. My neighbor gave me a cheapo wet saw from Harbor Freight that did the job but was a messy and crude affair - hindsight being clear I'd rent a good one rather than do that again.
Used mastic to set the tiles and that was straightforward. I made the mistake of actually reading and exactly following the grout instructions and it was too dry - like wet beach sand and it took too long to apply in a fairly awkward space. I mixed a second batch that was creamier and finished it. Really had to stay on it with a sponge so it didn't dry too much - and no matter how much plastic I put down you still wind up with that crap everywhere and are still cleaning up gritty crapola for days. It came out very nice. Waiting until tomorrow for full cure and then apply the sealant and color matched caulk.
Lessons learned - throw away the tile nipper and rod saw. Rent a better wet saw. Don't do this again anytime soon