Attaching 1099-R forms to 1040 (2020 Tax Year)

While I typically e-file, I have to file the final return for my late mother so I have to print and mail in her return along with IRS Form 56 as the personal representative of her estate.  That said, how should I "attach" her 1099-R forms to her return.  Before the dawn of TurboTax, the old tax forms were pretty specific about how and where you should staple these forms to the first page of the 1040. Now, it just states that I should attach them to the return. Pretty vague.  Any help would be appreciated.