INTRUDUCTION
Play Senna if you want to carry as a support.
Senna is easy to play but hard to master.
Senna q is a heal and damage ability with high range and onhit effects, with q you can target minions, champions, monsters and wards.
Senna w is long range delayed root that can doo AoE cc.
Senna E is multi-ally camuflage that only reveals you when near pink ward or enemy champ.
Senna R is golobal AoE damage and shield.

Support Senna wants to slowly poke enemies from far away.
Farming souls is important but if you need to expose yourself to danger just let the soul fade away. Sustain with fleet and dont be afraid to use cokies early. You will have mana with support item + presence of mind.
Roaming on Senna can be hard but very rewarding so only do it if you are confident in your abilites.

You want to stay with your team farm from enemy champions also dont forget to ward as a support should. If the lanes are pushed in farm souls when your jg takes a camp.
Dont use sums for 1 kill in late game only in teamfights.
Use your range to space and kite in fight if assassins or burst champs want to engage on you stay near tanky allies.

Thanky you for reading my first guide I hope it helps.