How do I prevent users from access wordpress dashboard?

I am using Edu-Clean + Q&A. When I tried to post a question, as a normal user, I was asked to register and submit question. Ok, fine. I did that. But when I logged as this user, I had access to dashboard. Even with just a few options to the user on the dashboard, I do not want that. I just want users to have access to front-end. I mean, posting questions and answers, editing, reporting, viewing must be only doable on the front-end. How can I configure the plugin for that?