Filed 2022 taxes, but since have received a schedule k1. how do I amend the tax return to include this schedule??

See this TurboTax support FAQ for amending a tax return - https://ttlc.intuit.com/turbotax-support/en-us/help-article/tax-return/amend-change-correct-return-already-filed/L4VjJ9BA2_US_en_US?uid=ld1n99kr

To enter a Schedule K-1

Click on Federal Taxes (Personal using Home and Business)
Click on Wages and Income (Personal Income using Home and Business)
Click on I'll choose what I work on (if shown)
Scroll down to Business Items (Business Investment and Estate/Trust Income using Home and Business)
On Schedule K-1, click on the start or update button

The directions to amend omit one very important step.  Before you amend make a backup copy of your tax file and pdf files.  Amending will overwrite the original and you will lose the original files.