Where do I enter 1099-DIV entry in turbo tax for box 2f (non-dividend distributions)?

You need to clarify. ...which do you mean?

Box 3: is non-dividend distributions.

Box 2f: is a so-called "Section 897 Capital Gain" and is not reported by US Person on a Personal tax return...and is thus absent in 1099-DIV form in the TTX personal software.