From the image below, if we focus on the first qubit, we know after Hadamard (state 1) $|0\rangle$ will become $|+\rangle$ and the second qubit $|1\rangle$ will become $|-\rangle$.
What exactly would the result be after $U_f$? I understand that $U_f$ performs a CNOT gate on the qubits. But how is this result shown? By this I mean the image below is it (the equation for state 2), $|0\rangle$, $|1\rangle$, $|+\rangle$ or $|-\rangle$ and why is it that specific one? For instance, I presume state 2 would be $|-\rangle$? is it simply the process that if it was previously $|+\rangle$ then it just flips after going through CNOT gate to $|-\rangle$? In which state 3 then results in it being $|1\rangle$ ?