Geometric construction of linear complex of planes of $B_3$ type

Using invariant geometric images of a trivector of type $(884; 400)$, we construct its basic group of automorphisms. We formulate and prove a theorem on necessary and sufficient conditions for determining of all planes of a linear complex associated with a trivector of a given type accurate to linear transformations of its automorphism group. In the process of proving of the theorem, we find all kinds of singular lines and for their nonsingular lines construct their polar hyperplanes.