You can have multiple TM data files just like a Word Processor. It pays to make sure the data file name is the same as the Main Menu name so you can tell which data file you have open.
To create a new TM Data File
Click on the Main Menu and select Change Data File
Click on the New Data File button - Do not enter a new filename yet
When the next window opens, enter a file name Easter.df1 and click on Save