Games are often presented using one ore more diagrams. One diagram contains some part of actual game or alternative sequence speculating what could have happened, if different move would have been played.
Typically each variation starts with new diagram definition. Without this moves in variation would not be included in export at all.
It is important to note that diagram is inserted at the start of the diagram, not at the end of diagram. So diagram with moves 50...100 shown is put before move 50 (and after move 49).
Multiple diagrams can be added using command File -> Print and Export wizard. Wizard uses various heuristics to put diagrams as normally needed. When starting to work with wizard, it is usually best not to alter options.
Use menu command Insert -> New Diagram to add one diagram at a time. This can be used to insert new diagrams diagrams after wizard has been used to create at least some diagrams.
Diagram can be modified using Edit button in property panel (left from diagram symbol in right hand side).
Modify Diagram Area
By default diagram includes whole board. Often it is desirable to include only part of board in diagram. Diagram area can be set when creating diagram in Print Area sheet.
In order to modify diagram area after diagram creation, go to somewhere within diagram. When within diagram, select desired area on board and use command Edit -> Set Diagram Area.
Diagram can be deleted using Delete button in property panel (in right hand side).