So i got 3 rules for this build:
NEVER JUNGLE.
NEVER MID.
ALLWAYS GO TOP.

ITEMS
You open the game wiht "RUBY CRYSTAL" (first you must have a lot of health!). Next item is "GIANT'S BELIT". You gut collect gold like (1415 gold xD) buy ****ing "WARMOG'S ARMOR". You have like 2000 helath soo buy other items. First you wanna some speed on your bear. So buy him a "BOOTS OF SWIFTNESS". Next item AD. Uf. So you open next item with "GIANT'S BELT" (first health), tehn "CHAIN VEST". Ofc you buying an "ATMA'S IMPALER" (why? becose you got 2% of your health in your AD so 4000 of helath 2% is like 80AD its good :D in the end you must have like 220 of AD). Next "THORNMAIL" (you want AD but you must have some armor soo you buy that). Next item. "FROZEN MALLET" first "GIANT'S BELT" then "PHAGE" then full item (you can take anyone on the filde one-on-one). Last you can pick for AP or ARMOR (armor recomended).
Last item sholud be: "SUNFIRE CAPE" (recomended) or "RYLAI'S CRYSTAL SCEPTER".

RUNES
Volibear don't have a lot of AS so you want to speed things up.
Mark: "Greater Mark of Alacrity" (+16% in AS)
Seal: "Greater Seal of Avarice" (that is for gold. must have a lot of gold income! +2.25 gold/10sec)
Glyph: "Greater Glyph of Alacrity" (+7% in AS)
Quintessence: "Greater Quintessence of Avarice" (+3 gold/10sec)

END: (+24% in Attack Speed and +5 gold/10sec)

SUMMONER SPELLS
Must have HEAL it is like noob but must have it!!!
PROMOTION extra gold and a lot of help! (alternative: Clarity but no help in the end of game)