Apply it. Simple as that.

The website is pretty self explanatory. I tool fafsa grants during my undergrad years. I think the difference between Grad and Undergrad is amount of money you can take as loan. As for Pell grant, it solely depends on your income and current social conditions which is basically you W2s and tax forms.

Undecided student does not make a whole difference when applying. Seems like you have not even started applying, there is form where you input your potential colleges/univ.

hope it helps.