presumably you have a relationship similar to this. (I'm not looking up the actual table and field names used in the starter solution, so you'll need to adapt this example as needed.)
Projects::ProjectID = Tasks::PojectID
Presumably, you've added a field for the yearly frequency needed for a given set of task records. We'll call it Frequency.
#Script should be performed from a layout based on Projects
Set variable [$ProjectID ; value: Projects::ProjectID ]
Set Variable [$I ; value: case ( Projects::Frequency = "bi monthly" ; 24 ; Projects::Frequency = "6 monthly" ; 2 ; Projects::Frequency = "Weekly" ; 52 ) ]
Go To layout [Tasks]
Exit Loop If [$I < 1]
Set Field [tasks::ProjectID ; $ProjectID]
Set Variable [$I ; $I - 1]
Go To layout [original layout]
There are several other methods possible, including a related table, that can be used to specify the number of tasks to be created.