I'm very new to project and have what I hope is not too annoyingly basic of a question!

I need to schedule multiple tasks, and link them in a way that they can occur in any order, but not simultaneously. Is there an easy way to do this? The only option I could think of was to add a resource and assign it to this task 100% but I thought that might go wrong down the road as I added other resources to the task.

The project I'm building it to manage a clinical trials team, so the reason the tasks cannot be simultaneous is that the trial participant obviously needs to be at them all.

Any help would be greatly appreciated!