I created a new clan and have been playing for days but it wont level up? is it a possibility the clan tag I used is taken already?
AAre you playing solo? To level up a clan outside of clan wars you need to be playing with at least one other clan member
As OUHATEME has already stated, you need to be playing in the same lobby as a fellow member of your clan to earn XP towards your clan. The only other way to earn XP is to compete in and win a clan war, which requires a minimum of 3 members in your clan.
As far as the clan tag if you were able to enter it and it took in the manage clan section then it is yours... Keep in mind that in game anyone can put anything as a clan tag even those that are already taken ... But other clans can't enter your clan tag in the app