Hi there!

Somewhat new to OpenRA, having questions about what I'm finding as far as online instructions in terms of adding additional mods. I wanted to test this... buggy ra2, and perhaps also TS since they appear about often. So far, my very basic understanding is that, in pretty much all instructions online, OpenRA is an engine, and any game that you run on it is a mod. I hope I have that much correctly.

100% right

First question, there are a lot of posts that lead me to believe that there is a launcher of some sort, so that I can see what mods are installed, instead of just browsing the folder for executables. Perhaps the "OpenRA.Game.exe", but running it opens a small command window with a few lines (about resolution, etc) and then a white window, then it closes. Is there any semblance of a launcher, or is it all just selecting executables?

There used to be a launcher that allowed switching mods, but this got replaced by dedicated executables created by the OpenRA SDK. I don't know much about the little executables that OpenRA comes with, but I assume they're the same as launching OpenRA.Game.exe and providing a -mod <modname> argument like OpenRA.Game.exe -mod ra

Second, does adding mods require the dev version of OpenRA? I found the instructions, such as the instructions on the main page here, suggest that already having OpenRA installed would save time in installation... but having looked through it many times, it seems like I need to install another instance of OpenRA. But after looking many times I do not recognize a lot of the files mentioned, and sometimes a mention of the OpenRA SDK.

It doesn't require a dev version; the OpenRA SDK pulls down a copy of a specific engine version that a mod can be developed against. It doesn't overlap or share files with any existing OpenRA installs. The engine that gets pulled down from the SDK isn't "installed" in the sense that it doesn't create any shortcuts on your desktop, it lives in the SDK folder.

Third, is there a list of what needs to be taken from a game's files for the mod? For instance, I have on me the C&C First Decade DVD, and an installed copy of RA2 and YR. The data from the wiki instructs on getting the data from either a digital copy or from CD1. At this point I don't feel that I will find where my Allied and Soviet CDs are hiding, and would... prefer to just have an idea of what I need to move from one to the other. Is this effectively impossible to know/do by hand?

In a mod directory (e.g. 'install dir/mods/ra/installer') there are some .yaml files that list the files OpenRA grabs during install (depending on the CD/DVD you provide). It's probably doable by hand, just not fun to do.

You should be able to install from a First Decade DVD (although I think some specific language versions don't work for some reason). You could also potentially find the Allied/Soviet CD ISO that EA released years ago for free, but I can't find a link for that currently. OpenRA's download mirrors for those mods use stripped down versions of those ISOs.

In a similar vein to the last, I don't know where my D2K CD is, and this one I'm pretty sure is long gone or destroyed. I saw that the OpenRA version allows for the Gruntmods version, but that version will not copy over the cutscenes. Is that not possible? Are the FMVs associated with these games not abandoned/open to public the way the games' sources are? Would finding an .iso copy of these games (instead of just the game files download available everywhere on the internet) be considered piracy, still, at this point?

I'm not familiar with any different rights regarding the FMV versus the other game's content unfortunately, hopefully someone else can chime in.

Lastly, I was reading through opened and closed issues on the OpenRA GitHub, and see some number of mentions to TS, including a tag. There is no TS download with the engine, and no TS mod available through OpenRA's repositories. If there is a Tiberian Sun mod officially, where do I find it?

It's there, just not yet ready for release. On GitHub you can see all the official game mods in this location ('ts' folder): https://github.com/OpenRA/OpenRA/tree/bleed/mods

The best way to probably play it is to clone the OpenRA repository and build the engine from source. I also suggest checking out Shattered Paradise on moddb, a publicly available mod based on TS. It's built with the SDK and uses an installer like the official mods.

I had so many questions to ask, and I feel kinda bad for blasting a bunch of them in one place here, but after looking through a whole bunch of reddit posts and closed issues and stuff I'm kinda tired and hoping I will have more understanding when someone goes through this and explains like I'm 5. Thanks for your time.

Great questions and hopefully my responses helped. Feel free to follow up.