You can create gates different ways, depending on your preference and what other components you want to model at the same time. This task describes how to create a gate using a node as a reference point.
(Geometry tab > Create panel > Nodes > Node By Offset).
(Geometry tab > Create panel > Curves > Create Line).
Browse next to the Create as box.
and select Generate Mesh. Alternatively, click
(Mesh tab > Mesh panel > Generate Mesh).