Can, got a 1099 div that i did not include in my 18 return. did the 1040x. printed the 1040x and 1040 with changes. i need to sign and send both forms back with my check?

Hi. got a late 1099 div. i did the 1040x. when i printed out the forms the 1099x printed along with a 1040 with changes. do i sign all the places for a signature on both forms and send them both in with my check? the instructions for this part is confusing. so i am guessing i send the 2 forms in signed with a check.  thanks