Multiple UV for unwrapped object Creating a plan of a room with 2 types of wallpaper.
I am using a UV map for each wallpaper.
I managed to get the UV map for wallpaper 1 (called StripeWallpaperLivingRoom) to successfully apply to the first set of walls. At this time, during development, I had unwrapped the other walls with this map but was going to sort that out when applying the second wallpaper (PlumWallpaperLivingRoom) to these walls.
I am attempting that now and unwrapped these walls so that they appeared default blank. However, although I have the unwrap mesh set up correctly aligned for my second wallpaper, it is not reflecting on the actual wall render.
The image for the correctly rendering StripeWallpaperLivingRoom is called 20-944_3.jpg and PlumWallpaperLivingRoom is called graham-brown-wallpaper-20-200-76_1000.jpg.
In Materials, these are called StriaStripe and StriaPlum respectively.
The Texture property does seem to only reflect the 20-944_3.jpg so maybe I should have done something here?? Also, even though I did unwrap to remove from the original UV map, the maps for the original 3 walls have appeared randomly on the original StripeWallpaperLivingRoom  and I think this is overriding my new PlumWallpaperLivingRoom map.
I am still a NOOB so if you can see where my misunderstanding is, please can you explain in detail. Thanks.
I am attaching screen prints to relate this info to.
You have two materials for one object: StriaStripe and StriaPlum. StriaStripe is on top and was put on the object first, and therefor the object is shown with that material.
If you delete StriaStripe in the Material Properties tab, the object will only have StriaPlum as a material, and then you can see it on your object.
But maybe you don't want to delete it.
In that case you have to select StriaPlum in the Material Properties (click it and it will have a gray bar over it). Then go into Edit Mode with Tab  and press A  to select all the faces of your object. Then click Assign (under the material list in the Material Properties tab), and the faces will get the selected material. Now the object is shown with the other material.
So with the Assign button you can give different materials to different faces, and one object can also have a material on part of the faces, and another material on other faces.