For a federal tax return you only send the Form 1040 and any supporting forms and schedules. There will be an Attachment Sequence Number located in the upper right corner of the forms and schedules that are required to be sent with the federal return. All other pages in the PDF are informational for your use only.
Print, sign, date and mail the tax return to the IRS. Include with the mailed return any forms W-2 and 1099 which have taxes withheld. Go to this IRS website for mailing addresses - https://www.irs.gov/filing/where-to-file-paper-tax-returns-with-or-without-a-payment
There are no penalties for filing a tax return after the due date if filing for a tax refund or there are no taxes owed.