It is easy to derive the commutation and anticommutation rules for the fermionic creation operators
\( a_\alpha^{\dagger} \). Using the antisymmetry of the states
(3)
$$
\begin{equation}
|\alpha_1\dots \alpha_i\dots \alpha_k\dots \alpha_n\rangle_{\mathrm{AS}} =
- |\alpha_1\dots \alpha_k\dots \alpha_i\dots \alpha_n\rangle_{\mathrm{AS}} \tag{4}
\end{equation}
$$
we obtain
$$
\begin{equation}
a_{\alpha_i}^{\dagger} a_{\alpha_k}^{\dagger} = - a_{\alpha_k}^{\dagger} a_{\alpha_i}^{\dagger} \tag{5}
\end{equation}
$$