The first blank datasheet is opened automatically with a new project.
Subsequent datasheets can be added to the project via:
File→New datasheet (Ctrl+D) 
New datasheet button in the Project Manager. Datasheets can be deleted via:
Delete Sheet (Shift+Del) on the name of a datasheet in the Navigation tree,
button →Delete in the Project Manager, if a datasheet is selected.
Note, however, that if you have reports or a map attached to a datasheet, deleting the datasheet also deletes any reports/maps assigned to it.
Datasheets can be described in the Project Manager by adding a name, title or a note.
Data sheets created in PQStat can be exported to csv, txt , dbf and xls formats. Exporting data is done in the Project Manager via the
button→Seve Sheet to…, if a datasheet is selected.