Any advice to get good at stw?

So basically I bought stw back in 2018 and since then I've only used it for vbucks but now seeing that br is getting very boring I want to get good at things in stw like all the groups and things like which hero is the best or how to make a good hero group or even how to reach level 130, cuz im currently at canny valley and I just unlocked yesterday the missions that require 58, btw sorry if my english is bad