do i files last year's taxes with this year's taxes or do i file them separately?

[Mike9241]

each year's income and expenses can only be reported on that year's return.   2023 and prior years can no longer be prepared online. you'll need the desktop version. full PC or Mac, prior years cannot be e-filed

system requirements:

https://ttlc.intuit.com/turbotax-support/en-us/help-article/product-system-requirements/minimum-syst... 

to purchase the 2023 desktop version

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

also available from other vendors. Those that offer a steep discount may not be legitimate.