When to use an F test and when to use a T test for a given regression?

The F-test tests the significance of all of the slope coefficients en masse.

You can use a t-test to test each slope individually.

So, if I use individually each slope coefficients to arrive at a conclusion using t test that they are significant, then can I say the same for F stat also, without conducting the f test because I have tested each coefficient using the t test?

That’s correct.