First, let's welcome you to CFS2, Mud.  I think you will find it to be the most flexible of any of the many flight sim programs. 

Secondly, I want to caution you against just jumping off the deep end so soon with regard to addons.   This is a proven formula for disaster.....go slow, as there is a learning curve.   Get accustomed to the standard game before trying to do addons.  Otherwise, you will most certainly  screw the pooch and endup with corrupted install.   

It's best to start your addons simply with something like a new airplane or ship, or even a simple mod like fixing thje stock gunsight so that it is accurately aligned.  When you need specific help, it's always available here. 

The HUD display is already standard in the game....see display cycling commands in Help. 

There are many very good WWI addons available from various sites....and planes, planes, planes here at SimV and at the other flightsim sites.