I installed Projectoria and created my first project ... now what?

Are you sure you read the .ppt user manual ?
demo.projectorria.org/manual/manual.php?page=53&tag=activity :evil:

Requested = wanted by client (wished)
Validated = agreed by all parts (committed)
Assigned (not for dates, just for work !) = defined in the assignments, defining requested (by project leader) work for resources (may be challenging validated work...)
Real = really done (start date = when stared, end date = when ended, real work = really done work)
Left (not for dates, just for work !) = work left to finish the work
Planned Work = Real Work + Left Work = Re-estimated work
Planned dates = calculated by planning => planning dispatches left work on resources depending on avalability and planning priorities (see planning for information on priorities)

Hope it's clear.

- Do I use the use the "requested date" fields?.

No, in the described case, you need to set validated dates

Who is going (and how) to update from "requested" to "validated".

You

In the way you describe it, you will have to define planning mode as "fixed duration".
This way, you should obtain what you expect.

But it is not the best way (to my opinion) to use Project'Or RIA.
Project'Or RIA default way of working can be considered like MS-Project if you use MS-Project with "work driven" tasks.
This means that planning is based on Work, not on duration.
Let's say you have tasks A an B. What you can easily know (I guess) is : how much work is needed to execute each task. For instance A is 10 man*days, B is 5 man*days.
OK.
Now, what about duration of these tasks ? You may assume A is 10 days, B is 5 days.
I will not. My answer is : all dependes on assignment.
If you only have one resource working, then possibly it will fit your first guess :

If you have two resources, things may slightly change if you assign one task each :

And you can change all things if you split the work on each resource for both tasks :

Now, it's up to you to know who can work on each task, if several resources can work on each task, and so on. You will then get a real planning no only a beautifull Gannt with some bars on.
This is what I call Project Management.

Project'Or RIA will help you to get a real planning, not only a drawing of some bars on a Gantt.