Install the spellflash addons for each class for begining so you learn the rotations and such abit easier , DBM PVP mods,

Noxxic com for info on the class as they give pvp builds, reforge help , gemming etc (all dependant on your preference for PVE i just gem 320 crit in every socket and reforge for crit ,in PVP id say gem for the most PVP resiliance)

as for anything inbetween icy veins is a good choice and when arenas and the like come back properly when you have a good "feel" for your class id say try gladius but i personally dont use it i find it more of an annoyance with my other PVP addons and how i play with friends .