What exactly do you mean by "control"?
They should, after successful registration/validation go into the registered users group. If you want them in additional groups, then you need to create promotions based upon the criteria that are offered to automate the promotion.
Don't get stuck on the "old way" of user groups that other software scripts use in which one goes into a main group for different things. All users should go into a registered group, which has the minimal permissions you want them to have - then run a promotion to add them into secondary groups that offer additional benefits.
For a good explanation, review Brogan's guide: https://xenforo.com/community/resources/implementing-permissions-across-multiple-user-groups.358/