Hey ThaZeus,
After Extracting I am left with two folders:Orbiter100830 and Texture_ Orbiter_2012_100830 so... What do I do with these?
Your goal is to get a root directory of Orbiter (e.g. c:\Orbiter or for me o:\Orbiter). Inside here, the top directories will include: Config, Doc, Meshes, Modules, Orbitersdk, Scenarios, Textures ... etc. You will also find orbiter.exe and orbiter_ng.exe.
When you download an addon (e.g. a vessel, some scenery, a multifunction display (MFD) utility), you need to look at the file to see how it will overlay on this new Orbiter directory, as follows:
1. If it's an .exe, then run it and i'll usually be an installer asking for your Orbiter directory (e.g. OrbiterSound is like this).
2. If it's a zip file, open it up to double-check you can see some of those expected directories in the top level (e.g. D3D9ClientR15.zip is like this), and if so, then go back to the .zip, right-mouse Extract All... and set the target to c:\orbiter (or wherever your Orbiter is). This causes the addon to overlay and augment the core install of Orbiter.
3. If it's a zip file, it may occasionally have an .EXE inside (e.g. PayloadManagerForOrbiter.zip). In this case, extract to a temp folder and execute the .exe.
4. If it's another kind of compressed package (e.g. .rar, as you may find for say IMS RC9.rar), then you need a free unzipper such as 7zip for those ones).
It's usually a good idea to keep a downloads directory somewhere close to your Orbiter (e.g. mine is o:\OrbDL). The reason for this is so if you screw up your install by deleting something by mistake, then you can rebuild the whole Orbiter install in say 10-15 mins. Also if you get into some of the multi-flight missions here, such as OFMM (Orbiter Forum Mission to Mars), or Orbiter Forum Space Station, then you will need to build a dedicated Orbiter installation using exactly the components that the mission designer asks for.
On your graphics client... the default orbiter.exe runs DirectX 7 for compatibility, and although being 100% stable and works perfectly, is much slower than implementations with dedicated graphics engines that leverage much later DirectX. Those engines are all labors of love from graphics devs in this froum (and we all owe them hugely for the eye-candy they generate). So when you refer to D3D9ClientR15.zip, this is the most popular and stable DirectX 9 client. Simply unzip it and overlay over your Orbiter directory, and then use the orbiter_ng.exe client (no embedded graphics client), and set up the Video components as you like them.
Some things I recommend you finding and installing to get you going (it's 100% subjective ... and there's thousands of things to choose from as well):
Sound ... OrbiterSound40_20121120_setup.exe
Vessels ... XR2Ravenstar-1.6a.zip, XR5Vanguard-1.9a.zip, plus UCGO30_2010_20140109.exe.
Bases ... Wideawake_International.zip, cssc_ v1_0_2.zip
Graphics ... D3D9ClientR15.zip
Launch assistance ... LaunchMFD=v.1.6.3-2010.zip
Trajectory planning ... IMFD55.zip and TransX-2014.04.26-Auto-Center-fix.zip
Align and docking to e.g. ISS ... RV_Orientation v3.02.zip
Burn calculators ... BurnTimeCalcMFD-v.2.7.zip
Base alignment ... BaseSyncMFD v2.5.zip
Reentry guidance ... Glideslope 2 (GS2_3_2013.12.01b.zip)
After that ... more scenery (depending on how much disk space you have, as these can be big), more realistic and historical ships and missions (e.g. Apollo, Soyuz), more fantasy things (e.g. deep space cruisers and things from SciFi series), remote bases on Mars and further away. Or if you have an idea, you can make your own ships and screens and roll them directly into the game.
Shout if you need anything...