Make a .mat file to have a material library of Corona mats:
1) In the Material Editor, under the "Material/Map Browser" window there is a down arrow next to the search box. Click that then choose "new material library".
2) When it pops up in the list below, right click it and choose "rename group" to rename it to something like "Corona Mats".
3) Right click on the group again then there should be a line that points to where the file exists with an arrow pointing right. Highlight that then click "save as" to save the .mat file somewhere.
4) Open the material files you downloaded and find the material under the scene materials or sample slots drop down in the material/map browser. Right click it and select "copy to...", then select the .mat file you created.
I would then suggest to go back to step 3 and save the .mat file after copying the materials to it since they are in different files.
As for the maps/materials that are Corona specific, I do not believe there is a collective document/post on what they all do, though most are similar to those that vray uses. Those maps/mats are:
Mats
CoronaLightMtl
CoronaMtl
CoronaPortalMtl
CoronaRaySwitchMtl
CoronaShadowCatcherMtl
CoronaVolumeMtl
Maps
CoronaAO
CoronaFractal2D
CoronaFrontBackMap
CoronaMapOutput
CoronaMixTex
CoronaNormalTex
CoronaRaySwitchTex
CoronaSky
CoronaSolidTex
CoronaWireTex
There might be more in the daily builds, but I'm not certain of that. I don't use all of those, so there are a few that I am unfamiliar with since I've never used them. To be honest, I wouldn't mind a page/post/doc, whatever, that describes each of them as a help/reference doc. I think some are on the Corona Wiki page, but I think they could be explained more by the advanced users and dev team here.
