After you file

I have not filed my return yet. How do I add form 8915 to my return to show the IRS that my 401k withdrawal was a qualified Covid related withdrawal? I took out 20k from my 401k and I either want to file 33%  of it over the next three years or pay it all back but I need to include 8915 in my return and I don't see any way to do that. very frustrated we are on March 3rd and still nothing about this.