I would probably be able to help you with any questions you might have since I worked at the IRS for 28 years, but your question is too broad to answer it here. If you are going to be filing for the first time, it's possible you will be able to file a 1040 EZ or a 1040A rather than a 1040. For starters you will need all your W-2s and 1099s. You have to have, and provide copies to the IRS, all forms or statements that back up the withholding credit you show on the return. If you go to IRSv, you can find most anything you need to know. Publication 17 is probably your best source of information to found in one place. We used it as a reference for almost everything. I would be happy to help you if you like. Just leave a message in my Shout box, and I'll get back to you.
You will need: Your W-2 form from employer(s), the employer's ID #, name & address. If you are not itemizing, then you should be able to do your 1040EZ. Itemizing is done when you own your home, make charitable deductions, deduct property taxes, etc.