Assigning Resources

Hello All,

I've got two questions about a model i am working on. I have four different rooms in which doctors see patients. At this moment every 20 minutes 1 of these patients arrive (so in total 4) but it is also possible that the arrival of these patient is somewhat earlier or later as expected. How can i model this in a easy way?

Furthermore, every patient has 3 test before seeing the doctor. 1 test is seperate, but the other two will happen after each other. For example (1-2-3). But it is also possible that the patient goes (1-3-2). So while patient 1 is in test 2, another patient can have test 3. When both are ready they switch and have respectively test 2 and 3. Does anyone know how i can deal with that. The patient are in a waitingroom when they will be called for test 2 and 3.

Kind regards,