Foundationalism is a position built around basic beliefs. A basic belief is a belief that doesn't need other beliefs for its justification. What kind of argument could you give for this position? Maybe something like this.
I see a brown table. I can't think of any other belief that could be a reason for my believing that other than that I just see a brown table. That's my belief.
This can be easily dispensed with, though. That belief could be contingent on the fact that you know how the word 'brown' functions as a concept for BROWN and you know how TABLE is another concept. So, maybe unaware to you at first, you could always give reasons for any beliefs you have and so no belief is basic. Foundationalism is false.
I really do think it's as simple as all that.