It is well known that any two subgroups of order $p$ in $\operatorname{GL}_{2}( \mathbb{Z}/p\mathbb{Z})$ are conjugate. Then there is one possible semidirect product of the form $$(\mathbb{Z}/p\mathbb{Z})^{2}\rtimes \mathbb{Z}/p\mathbb{Z}.$$ But this is not true for $\operatorname{GL}_{3}( \mathbb{Z}/p\mathbb{Z})$.
I want to know the number of isomorphism classes are for semidirect products of the form $$(\mathbb{Z}/p\mathbb{Z})^{3}\rtimes \mathbb{Z}/p\mathbb{Z}.$$
Any help would be appreciated so much. Thank you all.