This question might be a better fit for the Short Answers To Simple questions thread.

In terms of the Napoleonic Wars, Prussia directly participated in three: the Fourth, Sixth, and Seventh.

During the Fourth, the army was organized into divisions, this being implemented at the outset of the campaign. These divisions generally had organic artillery, cavalry, and infantry. Divisions typically had two infantry brigades and one cavalry brigade, these being largely ad-hoc formations without permanent headquarters staff. This war began with a devastating defeat for Prussia, and got worse from there; after the treaties were signed, the Prussian army was limited to 42,000 men. The divisional level was abolished.

In the Sixth and Seventh, the army was organized into brigades, which in the Sixth usually consisted of a fusilier regiment, two infantry regiments, a cavalry regiment, and an artillery battery. Prussian brigades could theoretically be as strong as some divisions, having seven infantry battalions [one of grenadiers being pulled from the infantry regiments] combined with the auxiliary arms. In practice, there was substantial variation, since Prussia mobilized for war in emergency conditions. These brigades were grouped directly into corps, which had their own cavalry and artillery reserves. In the Seventh, all cavalry and artillery was under the corps commanders' control, to be parceled out to the brigades or held in reserve as he saw fit.