Hello and thank you for reading my build for Rammus. This is a standard tanky Rammus build with a few changed. Such as, I play Rammus as a Carry Tank. If you play with me while i'm Rammus it would make more since however, It basically involves dominating early laning (with a good teammate) and destroying later game.

For early game:

Stay in the bushes and let your teammate fight the minions and try not to get spotted any. Normally I'll let the enemy push back a wave or two till their closer to my turret and i'm level 3. At this point you and your teammate attack, Start off with Rolling into them ((or flash-rolling into them)) and taunt the weakest of the two and shield.
Your button's should always be Q to E to W to R.

For when enemy's are gone:

I like to go bottom so when the enemy's are killed or missing I go and get Blue then wolves and prep for a "gank" from the water bushes.

For later game:

Taunt and let them beat themselves up on you.

For any time in between:

Rammus is a very good ganker. If mid is getting shut down or I just want to have fun, roll to middle and get a free kill or just play with mid a few seconds then go top.

With the runes its mainly to cover at early game when Rammus has lower HP, as he starts off with less than tanky HP. It also gives him some bonus AD from his passive. You can be very aggressive early game with these runes.

Ball up the flash into someone for the Lul.