Here you are! You have decided that you want to file or that you must file. You have determined your tax residency status here. This site is help you understand a tax return that you have in your hand. If you do not have a tax return from a previous year, use blank forms.
Understanding your taxes will start with the 1040 or the 1040NR and move backwards. Look at all entries on your 1040. Some you will easily understand but some are totally confusing (even to some tax preparers sadly). If you click on a line that you do not understand, I will try to explain where the figures came from. There may be lines that confuse you because you were sure that you should have that deduction or credit but mysteriously the tax preparer or software did not 'give' it to you. Exploring that line should help you understand why there is no entry. It also might help you to go back to the tax preparer or software to correct the entry if you determine that you really do have the right to a particular deduction or credit.