Project Manager - Link between Schedule and Resource request

Hi all, I'm using the CLOUD version of 3DEXP (for managing the integration of the platform) and we are integrating / configuring an ON-PREM system for company wide roll-out.

What is "the link" between the Schedule with allocated resources and the Resource Request.

link possibilities:

1. Is the resource Request updated with the actual allocations?

2. Can resources be allocated without resource requests  (and approval)?

3. When a resource manager doesn't confirm the allocation of the resource to a project, how is the project (with it's allocations) impacted. for example resource X schedule for 3 months - what happens wit his task?

4. ... ? maybe other users see more possibilities --> please add in comments.

For the above what is the level of configuration required?

Is there a webinar or detailed video of the possibilities available?

Thanks in advance,

@AL ​​​​​​​