Volibear is a great champion to climb out of any elo!
It requires basic mechanics and as long as you build correctly and follow this simple guide you will stay relevant in all parts of the game.
Volibear also has no real bad mactchups as you have a really strong 1v1 in the early game.

Volibear can start both red and blue ,depends what lane you are going to play through,you don't really need a leash but it doesn't hurt if you get one :)
After you do your buff just clear the rest of your camps(skipping krugs)and take scuttler(Voli can beat all junglers in a pure 1v1 at level 3 so it should be free.
After that you can look for a genk on either mid or a sidelane(u can always burn at least a flash)
While genking don't be afraid to use ur flash as a jungler's flash is always worth less than a laner's.
After genking reset and buy skirmisher's and boots and go straight to dragon.
Dragon's are IMO the most important objective in the game as getting the soul is almost always the best way to win the game.
Volibear can solo dragon but you should look for either mid or bot to help you with it.
!!!!!!!!!!!!!!ALWAYS BUY CONTROL WARDS IF YOU HAVE SPARE GOLD!!!!!!!!!!!!!!!!!!

After the early jungle play around the dragon's and look to continue full clearing.
Herald is an interesting objective,as it is either completey useless or can actually win a game if used perfectly.I personally avoid doing it but if you have nothing better to do...sure!Preferably use it to grant gold to ur carries(Stay outside of the plate gold range).
Another thing that Voli is great at is tower diving!After level 6 don't be afraid to call ur team to the botlane and FIESTA!

In the late game look to protect your carries with you support items and block skillshots.You can also just R on an enemy carry to nullify them from the fight if you carries are self-sufficient.
My favourite thing to do as Volibear is to just R the nexus towers at the end of the game,I call it the Mike Wazowski special move!