Starting from the top, it's a cooldown bar of Thunder Focus Tea, Essence Font and charges of Renewing Mist (as well as a remined to reapply Mystic Touch). Those are the main short-cd spells, we need to track and try to use as close to cooldown as possible (without overheal or wasting its effect, of course).
Underneath them is a colourised ReM bar which sets each Renewing Mist a colour as well as length: the shorter the ReM the shorter the bar. Colour also represents how little is left of an ReM: blue — over 20 seconds, light-blue — over 15 seconds, green — long (>10 seconds), yellow — medium (>5 & <10 seconds), red — short(<5 seconds). Also little bit of tonal difference allows to differ between them, when many were applied.
At the lowest there is a 12 second Big Wigs timer in a form of icons with a timer. It's specifically there so it composes a pair with a top bar (CD bar), so you can easily track both CDs and incoming abilities and know where you can spend a CD, and where you should conserve them for the BigDickBurst.
To the left there is a ReM Counter, left number represents amount of injured (<93%) people with ReM, while the right one the total amount of ReMs applied.