Hi Fast Eddie,
If you have already scored your piece(s) in standard notation then a simple way to add Tablature is as follows:
Select Edit > Instruments (this will open the instruments panel)
Click on >-Plucked Strings then Click on -Classical Guitar (Tablature) and click on the Add button
Click OK (this will add the TAB to your score)
Select all the bars in your original notated score and copy them
Click on the first Bar of your Tab and Paste. This will create a best estimate TAB.
Once you have done this, you will need to go through the tab to make sure it has selected the correct strings you wanted. If it hasn't, you can select the note within the tab and drag it to the correct string.