Online workshops are here to help you in your learning process, they allow you to receive advice from your expert, complete exercises, and interact with your course mates etc.
Although these are very important, attendance at online workshops is not compulsary.
If you have a prior appointment and cannot attend a workshop, don't worry! You can always watch it on replay 🙂
If there are other online workshops scheduled during your course, make sure you've signed up to them.