You can't "catch up" to your original return. You must wait until the IRS processes your original return and you receive a refund if you were getting one before you start the amended return. The form is 1040X and it is estimated to be available from TurboTax on 2/5/20.
DO NOT change your original tax return until you start the amended return. If you have already changed it from the way it was originally filed and accepted, you must change it back before you start the amended return. Wait until you receive the refund from your original return before beginning your amended return to make sure you enter the correct amount. Here is an FAQ to help you:
https://ttlc.intuit.com/questions/1894381-how-to-amend-change-or-correct-a-return-you-already-filed
