Download a plugin in zip file is easy, after : you must install and activate it.
You need a FTP access to use your own plugin on LimeSurvey. If you can it’s better a ssh or sftp access.
Get the plugin ready
You have two way to download the plugin : a compressed file (in general a zip file) or a GIT repo.
If you download a compressed file : you must unpack it first. You can use for such purpose 7-zip if you use MS-windows. By GIT, you have already a directory.
Move the plugin to the server
You must upload the plugin to the server. For such usage you need a FTP or, better, a SFTP access. You must upload the complete directory of the plugin in the limesurvey_base_directory/plugins/ directory.
You must put whole content of the plugin directory inside it’s own directory and the directory name must be same than the plugin php filename . For example if you plugin name examplePlugin with a file examplePlugin.php: you must have finally
If you have more content than one PHP file : all content must be moved to the directory. For example
Activate the plugin
After moving the directory in plugins directory: you must activate it.
In 2.06 and lesser version : click on the menu or
In 2.50 and upper version : go to Configuration and after to Plugin Manager menu.
Search your plugin in the list, and activate with the button. If the plugin have global settings : you see a second button.