If there is no overlap between the problems then the best way forward is to craft a solution for each problem one at a time. It is best to find a system that works for you in terms of finding a solution. My process is as follows:
- Define the problem
- Find why out the problem is occurring
- Craft a solution
- Test the solution
- Launch update
For instance, I take one problem. In this case it is difficulty/frustration with booking an appointment. Then I set out to find out the cause of it. In this situation I run a round of usability testing and see that people have difficulty finding the "booking" button. Next, I create drafts for a few different solutions for the issue and do A/B testing to see which one works best. Finally, I run another round of usability testing to make sure the product is working. If it is, then I implement the change. Now, I can move on to the next problem.
As you can see, since you already have a system, you know what your plan will be in terms of tackling each problem. So your next step is to pick the most serious one and start working on it.
Hope this helps