It is possible that you will need different templates. E.g, one week you want to be available on Saturdays, other weeks you don’t. Or one week you work by preference in location X, the other week you have more availability in location Y. 

Those are, together with others, all good reasons to have multiple templates.
Creating a new template is fairly simple:

Go to “Appointment hours” and click on the “+”

You should choose a name and a color for your template now:

Then you will need to select the dates or weeks when you want to apply the template. Of course, you can change this afterwards

You can select the dates by dragging and dropping (1), look for your template (2) and apply it (3) for a certain period (4)

After you have done this, you will need to open the template and repeat the steps made when you were adjusting your default template!

You are all set!