p ∧ q (i.e. "p and q") is true only if both p and q are true. This is the case for the first two rows, but not the third.
Similarly, (p ∧ q) ∧ r is true only if both p ∧ q and r are true. We know when p ∧ q is true, so (p ∧ q) ∧ r is true only when all three of p, q, and r are true. This happens only in the first row.
All other cases are false.
The table should look like this: