Entropy and Gibbs free energy

When asked about the spontaneity of a reaction in relation to enthalpy and entropy. Is it ok to use Gibb’s free energy equation G=H-TS to explain spontaneity?

Yes it is but just using Gibbs free energy may limit your answer to the question.
The approach usually in questions is to look at spontaneity and enthalpy so be careful to link the two.
No brain too small has a great explanation found here:

Hope that helps