The "Generate" option page offers the following options:
Use Precalculated Problems: If checked, problems are not newly generated but loaded from sudoku.pi-c-it.de (for both normal and X Sudokus approx. 25 000 precalculated are available). With this option checked, the "generation" of new Sudokus only takes a very short moment. If checked and an internet connection is not available, this option is ignored and the problem is generated locally. To prevent an overload of the remote site, the maximum value for problems in new booklets is set to 16 if the option is checked.
Minimum Number of Values in generated Problems: This value must be between 17 and 35. Even though there is no proof that Sudoku problems must contain at least 17 numbers, nobody has ever generated a problem with less values (in 2011, a "Brute-Force-Search" found no valid problem with less than 17 number, see here). The generation of problems with more than 35 values is very complex, therefore the upper limit is set to this value. This option is not available if "Generate Minimum Problems" is checked.
Generate Minimum Problems: If checked, the new generated problems are minimized (see "Minimal Problems").
Severity: The severity level of generated problems. This setting is also used for the selection of existing problems when a booklet is generated out of existing problems.
Select Level: If this option is set, the severity level can be selected prior the generation of a new problem. Otherwise the severity level of new problems is randomly selected out of the levels checked in this dialog. This option does influence the severity level of the problems in booklets.
Sudoku Types for Booklets: Option to set which types of Sudokus are generated for new booklets. If both types are checked the respective count is at random.
New Problems: The number of problems in new generated booklets.
Existing Problems: The number of problems in booklets generated out of existing problems. If the checkbox "unlimited" is checked all problems of the selected directory and all of its sub folders will be used for the booklet.
Auto Save Booklet Problems: If checked, problems generated for new booklets are automatically stored in a sub folder of the "Problem Directory". The name of this sub folder is made up of the current date and time.
Problem Directory: Problems are stored and loaded from this directory by default. This folder can changed by clicking the "..."-button.