How do I file multiple w-2s that I have not filed for this upcoming tax return

What do you mean by "multiple W-2's that have not filed?"  Do you mean they are all for income received in 2023?  If so, then you have a great answer from VolvoGirl.

Or do you mean you have W-2's from some past years that have never been filed?

If you mean you have W-2's from past years, you cannot put them all on one tax return.  Each tax year is separate and must be prepared using the forms and software that are specific to the year in which the income was received.  The forms and tax laws change, so you have to use the right software and forms that comply with the tax laws for the year you received the income.

You cannot change the tax year.   The current online program is for 2023 only.   Only a 2023 return can be prepared online and only a 2023 return can be e-filed.

Online preparation and e-filing for 2020, 2021, and  2022 is permanently closed.

To file a return for a prior tax year

 If you need to prepare a return for 2020, 2021, or 2022  you can purchase and download desktop software to do it, then print, sign,  and mail the return(s)

https://turbotax.intuit.com/personal-taxes/past-years-products/

You may also want to explore purchasing the software from various retailers such as Amazon, Costco, Best Buy, Walmart, Sam’s, etc.

Remember to prepare your state return as well—if you live in a state that has a state income tax.

https://ttlc.intuit.com/community/state-taxes/help/how-do-i-contact-my-state-department-of-revenue/00/25573 

When you mail a tax return, you need to attach any documents showing tax withheld, such as your W-2’s or any 1099’s.  Use a mailing service that will track it, such as UPS or certified mail so you will know the IRS/state received the return.

Federal and state returns must be in separate envelopes and they are mailed to different addresses.  Read the mailing instructions that print with your tax return carefully so you mail them to the right addresses.

Note:  The desktop software you need to prepare the prior year return must be installed/downloaded to a full PC or Mac.  It cannot be used on a mobile device.

If you are getting a refund, there is not a penalty for filing past the deadline.  If you owe taxes, the interest/penalties will be calculated by the IRS based on how much you owe and when they receive your return and payment. The IRS will bill you for this; it will not be calculated by TurboTax.