[SOLVED] Continuous activity - do not interrupt activity with another activity

I've been spending time getting to know this application in order to use it for teaching Project Management at a university. So far so good!

My question is, is it possible to set an activity to be continuous?
Obviously, there will be weekends (and sick days ideally), but can I at least make sure that a resource won't be diverted to another activity halfway through the current activity? I know this is rarely relevant as most tasks can be dropped and picked back up, but I can't stop cooking roast dinner halfway through without it taking longer overall!

For example, I have two tasks that use the same resource (called "Atelier"). One of these tasks is part of the critical path but starts after the earliest start date of the other one. The result is as below. What I would like is for one of the tasks to be delayed such that neither is interrupted by the other.

Thanks!

Okay, so this is ultimately up to the project manager to notice and handle correctly by adding dependencies. Thank you