The user would select the year they want to work with
Set up a field with global storage, such as Globals::gWorkingYear
Format it with your value list of years (radio buttons, drop down list or pop up menu)
I want the system to "prime" or automagically enter the current working year ID
In any tables where you have a year field and you want a new record in the table to automatically enter the year selected by the user, Find the field in Manage | database | fields and double click it to open Field Options. Click the auto-enter tab, select the "calculation" option and enter this expression:
Globals::gWorkingYear //use your table and field names in place of my example names.