Novice Question: Date-dimension for a fact!

[mixim]

Hello,

Me:
First of all, I am a complete novice. I have experience from Cognos BI report development. But always relational modeling. No true previous experience with OLAP style modeling or cubes.  So pardon any gaps in TM1 or my Cube concept understanding.

The background:
Using TM1 10.2 I am trying to build a simple register for the size of housing complexes in square meters. The thought is that that the cube in the end should be act as a data-source for Cognos BI to do simple reports. Each building has the same type of areas, but they vary in sizes and proportions.

The Question
How would you go about to model the cube in order for it to be possible to to enter a specific date via prompt and seeing the square meters for at that specific point of time. But also, what user did this?

Is the right appproach to create a date dimension for the building "fact" ? Is this done manually?
Also, is it possible to "grab" the current user who contributes a change, and add this user in eg a User dimension?

[mixim]

If my question is unclear, please let me know and I will try to clearify!