my grades were bad in high school.how do I redeem myself like what classes do I take in community college in order to transfer to university?

You make an appointment with an academic advisor at your community college to plot out your coursework. The academic advisor will know which course credits will transfer to your state universities. For instance, if you need to take remedial classes in math or English to prepare you for college-level work, the credits from those remedial classes may not transfer to a university. If you didn't develop good study habits in high school, you might want to start slowly and take less than a full course load so that you can develop those study habits and do well in your community college classes.