Very dependent on the plugin...
In the general case of code extensions, you have two categories, scripts and plugins.
Scripts are written in Scheme (hence the .scm extension) and go to the scripts folder in your Profile
Plugins come in two rather different forms: binary, for which you need the adequate form for your OS: .exe for windows, .app (I think) for OSX, and Python .py that run on all systems. Both types go in the plug-ins folder in your Profile
Once installed, plugins and scripts are called via a menu entry. Some add their menu entries somewhere in Filters but other places are possible when it makes sense. This is usually indicated in sole write-up.
Unless otherwise noted, the script applies to the image active when it is called, and if necessary to the active layer.
In the general case of code extensions, you have two categories, scripts and plugins.
Scripts are written in Scheme (hence the .scm extension) and go to the scripts folder in your Profile
Plugins come in two rather different forms: binary, for which you need the adequate form for your OS: .exe for windows, .app (I think) for OSX, and Python .py that run on all systems. Both types go in the plug-ins folder in your Profile
Once installed, plugins and scripts are called via a menu entry. Some add their menu entries somewhere in Filters but other places are possible when it makes sense. This is usually indicated in sole write-up.
Unless otherwise noted, the script applies to the image active when it is called, and if necessary to the active layer.