I creat country Québec but in the games , i can't play Québec

Did you make sure to assign the territory to the nation? if not what you have to do is assign the capital and then you will be able to assign all of the states

check the history file for quebec if its there check the state id that you assigned to quebec which you can look up on google but they are probably 466, 861, 860, 862, 863 and 468 because the fact the country is called quebec makes me think its quebec