I've figured it out. This can be done using the or concatenator "|" between days so, for example, DaysOfTheWeek.Friday | DaysOfTheWeek.Saturday.
A slight problem I've had, which is probably why I didn't figure this out right away, is that I'm working in VB and most of the examples on here are in C#, so I have been trying to understand the examples based on my rudimentary knowledge of C#, or by using the websites that translate beween VB and C#, but those websites don't always do the translation correctly. For those of you coding in VB, the method to include multiple days with a weekly trigger is to use the word "Or" as the concatenator, so for example, DaysOfTheWeek.Friday Or DaysOfTheWeek.Saturday.
In any case, I've got this resolved. By the way, this scheduler is an excellent piece of software.