So pls fellow dokkan gaffer, tell me which cards i should focus on
Since you're low on SSRs, i'd suggest grinding Story quests and rack up Dragon stones to spend on the guaranteed SSR banner. Most of it will be easy with SV (I don't know what team you can build with low Team Cost limit) and if you're just starting you'll be basically playing forever with the 3x EXP, ranking up all the time.
Regarding the SRs and Rs, I don't know by heart what they all do, but keep everything that has a special skill like Stun, Super Seal, Orb color changing, Perfect Guard (-30% or 50% enemy attack when guarding), reduce enemy attack, +HP when collecting orbs, etc.
Rs aren't always crap, that R Bulma for example is quite useful for stunning.
Keep units with links that give ki, like Prepared for Battle, Shocking Speed, and the like. They can complement your better characters by giving them more ki.
Also those with +2 Ki to a certain color, and those with Dokkan event specific passives and links, like the AGL Kid Trunks.
I suggest going through the Dokkan Battle Wikia, checking out the Dokkan events and what units have the relevant skills.
Also, don't immediately awaken all units you get, unless you really need the extra stats. If you keep them low, their cost will be almost always be lower, and it helps with the Super Strikes which have a team cost limit of 100 and where you can get some pretty good units (the current one, Trunks, isn't great, but most of the others are quite useful).
By not awakening everyone you'll also save money and materials, which can be short at the beginning.
And start increasing your character slots little by little. Also gather all the dragon balls and get all wishes (focus on the wishes that give you dragon stones, character storage).
Anything more specific, feel free to ask and we'll try to help.