RAIGOR is the hero with most stun abilities. Its my best hero and had expriences of it.Its one of the best hero for 5vs5 match. It don't like long guides so shall i tell u in short.(Inf.-Buy the following accordingly)
Beginning items-
* Ring of regeneration
* Ring of protection
* 2 Clarity Potion
* Healing Salve
* Ironwood Branch(sell it afterwards)

Items(buy according as i written)
* Arcane Boots
* Vladmir's Offering
* Aghanim's Scepter
* Linken's Sphere
* Heart of Tarrasque
* Monkey King Bar

Abilities

* Fissure
* Aftershock
* Enchant Totem
* Aftershock
* Enchant Totem
* Echo Slam
* Enchant Totem
* Aftershock
* Enchant Totem
* Aftershock
* Fissure
* Echo Slam
* Fissure
* Fissure