The 'Insert Fittings' dialog is part of the Kohera3D Piping module and can be found under 'Piping > Fit and Insert'.
Piping components are inserted (added) by choosing one or more pipe centerlines to attach them to.
Inserting an Elbow
Inserting a Tee
Inserting a Valve
→ See also Step By Step Instructions, Create Piping System, Piping Tools, Pipeline Explorer, Pipe Line List, and Fitting Pipe