Hello evryone and this is my 1st guide! I made it my own experience. It may not be the best guide but i like it and the win/loose rate of this is 10/3 so think for yourself. I dont really get all the options here so this will not appear as bright as other guides.
The thing you mast to know that you will have lots of health despite of fact that it says only 2.something thouthands on the guide board.

Those are almost standart abilities. However you should not underestimate Cho'Gath's Spikes it will do some truble for minions and the champ behind them. That is why you should take it about the same level as your Scream.

Those were my Morgana runes and they work perfect with this build.

You should not try to have some ward at the satrt because they are useless, no one will gank you at the start(even if they will you can escape with no worries because you have your Rupture and Flash). As you get some money buy boots. After you got Boots of Speed ypu can buy a ward and a few mana/ health potions. The next thing you do is upgrade them. After that get Catalyst, it will make 2 very important stats on low level to increase. Next step is buying NLrod which will make your Rupture hit way harder. The you get Rod of Ages wich is a must for Cho'Gath and deathcap to piss your enemies with the Rupture even more. You should start your crystal scepetr with a Giant Belt. This item works on all your abilities+ gives a decent hp bonus. Getting Liandrys Torment is a good idea because poking your enemys with Rupture will make it even more fun. If you get to the late game, sell Dorans ring and get a Frozen heart.

At the start try farming minions with Rupture and not coming too close to your oponent. As you get spikes you can piss enymy off while fighting minions. I do not recomend using Scram on minions.

I usually try feasting on big minions or jungle creatures(donr underestemate jungle creatures, they can survive your Feast). Try not to get in the fight wile having 3 or 5 stacks on they feast because they will go down to 1 or 2. For teamfights go for ADcarry or other champ like Katarina with all your abilities at once. Which should disable them for a bit and having a good chance of killing them.

Its easy to turrethug because you have got alot of disables which helps ypu to deal with up to 3 of incoming enemys at a time(when stacks on Feast are high). This build does not make you very tanky and you should not initiate a teamfight. But still keep the ADcarry kill in mind.

Ok now it is done. I am not really good in English so please leave where you find mistakes in comment.
Thank you for reading. Hope the guide was helpful :)