the tank/support is a Build for you how want to support your team and your AD carry in bot.
in level 1=if the enemy is aggressive try to stun the enemy as much as possible.to get the upper hand. But if they are playing def then your best hop is to do the same.

in level 2=if they are still playing aggressive you should do ragular E then Q combos if possible.(remember that you can do double the damage if you land a basic attack then your Q)
if you have push them to their tower you should back off and wait for them pusht ther lain. Sow you can cheat them out sow your AD gets some killes.

in level 3=do the same thing as in level 2 but whit tis combo instead E,W,Q.
(do this in your waiting for level 6

now it is time to push the enemy tower(if you can). If it's not capable to do then you should let them push sow your jungler or mid can come to gank. or you can yust do the E,W,Q combo and ult them sow your AD can pick up some more kills be for you start roming.
(if you have time try to tack Dragon whit your jungler and AD)

try to walk whit your AD(your not a possible damage dealer)and be redy to stun any target that has over extended.
You can allsow help the other lains to push through.