You ran into junk and damage panels, the game does have a tendency to not tell you until you lost, the saving grace really is you don't lose any energy when you lose.
now for your questions>Also what should I considered when building a team?
Read every skill carefully, a lot of the time it can save your ass to know exactly what every unit can and cannot do (especially since it's surprisingly easy for skills to step into the toes of someone else)>Is it beneficial to have multiple element on one team or the main focus is single element?
Single element, especially when you start to obtain stronger units, although for someone that just started you can still mix without too much issue> Can someone explain to me how to properly read a character skill please? Because most of these doesn't even make sense. Like, how do I make head or tails with this? Some of these descriptions get even worse than this.
Post them, i'll help with that.
also is that your pull? if it is you got a damn fine unit already.