Trying out plugins is very easy if you first install the plugins manager: https://sourceforge.net/p/sweethome3d/p ... 1.5.3.sh3p
Once that is installed you can just select a plugin you want to add, update, or remove.
You can read more about it here: http://daniels118.altervista.org/sh3d/pluginmanager/

There is no plugin to color walls in the 2Dview but there are a lot of other useful plugins. You should at a minimum install the advanced edit plugin and you will probably want the Roof and Staircase generator plugins too. The Pan3DView plugin gives you a better 3Dview experience.