Obligation of data entry order using data validation

Hello,

I need to create a sheet for my colleague to work on.

I set some custom data validation rules combination using AND function, and I need to add to these rules that the cell should not accept any entry unless another specific cell is filled first.

For example:

I need to restrict the entry in cell C3 using some sort of values and rules using custom AND function.

Now I need to add a restriction that cell F3 should not be empty, means that F3 should be filled first (F3 actually contains a data validation drop down list.

How to add this part to the AND formula in data validation?

PS: I tried adding And(F3<>""

and it did not work fine.