Welcome to EAW!
New players should know the great thing about EAW is you don't really have to install it. Once you have a copy of the EAW 1.2 files in a folder
ex. European Air War typically refered to as your "EAW folder" make sure you save an original copy.
The "EAW Folder" is the all-important concept to know of - that is where the addons are placed in EAW 1.2 at least.In later EAW Codegroup versions the ability to point to where addons are to be used was made possible as MrJelly above noted. Because you can upgrade in various ways.
You can upgrade the version, but also you can use Add-ons , which can be anything from the Planes graphics
aka 'Skins' to scenarios / missions sets, terrains, skys, gunsights, etc. and also the performance of the Flight Models, damage, gunnery and armaments, so forth.
The other option is to just download another version that is either an upgrade package or standalone / complete version.Since you are familiar with other combat air sims you probably know most people use some form of program or 'skin manager' to handle these add-ons. EAW has a long history of these in its early days people used stuff like 'STAB' and 'Skins-n-More' , see:
vonOben's Flight Sim ModsAnd also there were Enemy Coast Ahead and ECA Panel.
MrJelly made the OAW Selector a bit later then the heyday of EAW and OAW eventually replaced all those.
'Online Air Wars' became the thing and OAWunified was a complete set that is still available for 1.2 that offered a complete package and most importantly to upgrade the flight damage and gunnery model.
The EAWrp 'Realism Patch's developed by Knegel who was basically one of the best Aces of EAW and also had a fair amount of understanding of the technicals of EAW and the historical details of WWII fighters at least in the European Theatre of Operations
aka "ETO"Having the AI Cannon patch and Knegel's EAWrp is also essential for 1.2The gunnery in EAW 1.1 ~ 1.2 was bad
the gunnery shoots like a shotgun spread, the hitbubbles are huge, the AI's never can use the cannon and so forth like an arcade game. The first Cannon patch was 1.26 and that was the basics. There were previous hex-edited .exe's etc 1.1 BOB versions, etc but none of them had the AI cannon patch.Later the Codegroup got the code and made some new .exe's Anyway I am retired from EAW but just thought to make again clear the basics about the EAW folder and there is no reason not to try / use / have multiple versions of EAW on your PC. Some have dozens of them.
Just be sure to alway make a copy of your originals before you start.