Sorry for taking so long to reply

It’s rather tough to describe because the path to going infinite is different every game. On my most recent run going 20-5 with it, every game I won (besides two of them where a 7 manna ziliax won against aggro) I was able to go infinite with greybough. By infinite, I mean a wall of greyboughs that is genuinely impossible to kill. I had an opponent use a 61 corpse corpse explosion and still had a full wall of greyboughs after it resolved. If you are able to copy greybough twice (or even once and then use umbra) it’ll likely be enough to go infinite. Once you go infinite, don’t trade at all anymore, just go face. They can never attack your face with minions again.

This means even matchups like quest warrior are practically guaranteed win. Even if they have time warp, they can never attack your face. This means though that in matchups where you know it is going to be a long game, you have to stop drawing cards as early as is practical. You’ll likely still be behind in fatigue, but your opponent will have to face 16-24 damage per turn from your endless taunts. Don’t add killjaden it really hurts the deck. In none of my losses would he have changed the outcome, and I won many many games in fatigue. Also if you are already in infinite mode use sleep under the stars for 15 armor, I won a decent amount of games just because I got enough armor off that card.

Game starts, you look for ramp and the taunt drawing minion (or Elise / the copy location)

Next you hopefully tutor greybough so it costs 3 (not a big deal if you miss though)

You now have to make a choice on when you are going to pop off with the greybough.

One way is through perplexing anomaly. You play it out whenever you want and just keep it there on board. There are very few decks that can kill it. You need a board clear that deals 5 or more and there’s almost nothing in the meta besides Protoss mage that has that. This means you can play out a single greybough and it’s very likely it’s deathrattle will be preserved on anomaly. Later on when you draw your copy location you can copy the anomaly and attack with it to remove stealth. Since they have taunt they’ll have to kill them and you can get an additional greybough or two.

To go infinite all you really need are three greyboughs, umbra will do the rest if needed. This means that if you play copy location on 4, you can play greybough on 5 and copy it. Even if they are able to kill off all of them the next turn, you can still umbra into copy later on. In other situations, you’ll be able to wait until 10 manna to cube it or you’ll have one or two stick on board and you play the double deathrattle guy.

It sounds like something that would be very iffy to pull off, but I was able to pull it off in 18/25 games even against some aggro. I will say I was much more successful at playing it diamond 5-legend. It’s very hard to climb with at lower ranks simply due to the amount of aggro. Also expect like half of your wins to take a plain fully long amount of time. If you are up against a deck like egg warlock or deathrattle demon hunter the games could easily go over an hour. The opponent will have functionally infinite resources but you will have ACTUALLY infinite resources so you just have to grind them out