I have a form 1099B? How do I enter it on turbo-tax?

See the following FAQ.

Where do I enter a 1099-B?

on the 1099-B worksheet. in the search box type 1099-B. then use the jump to link to get to the form.

you should have come or maybe will come to question about selling any investments in 2020 - answer yes.

did you gt 1099-B - answer yes 

you then come to an option to import it or enter the transactions manually