This from a recent post i made,
If you are renting a server from a host and have full FTP access its much easier as you can download and install plugins yours self without having to ask the server host to do it ,
All you do (if above) is go to Umod.org plugins page and look at the plugins you want and download them to your pc (download folder) when you have them. open your server "dashboard" and look for (in my case) "File manager" open folder and you should have a folder that says IE: Server/Streamline/Oxide when you open the "Oxide" folder there will be a list of folders , CONFIG, DATA,LANG,LOGS and PLUGINS ,
Open the Plugins folder and you should have a menu that enables you to remove or upload plugins, if there is an upload button it will ask you to browse to file location and it will tell you that the file was uploaded and installed.
READ the document page for each plugin before you attempt to make any changes to the config/data/lang files for the plugin.
DO NOT MAKE ANY CHANGES TO THE .CS FILES IN THE ACTUAL PLUGIN FOLDER.
I have as you will note put streamline as the server name, you would of course use "blackbox (?) for the server name, the layout and method might also be different , BUT dont forget you have 24hour support from the server host and most of them are very helpful in showing you how to set up your server,
I had a very bad experience with Multiplay a few years ago the lasted for over 3-4 months and i moved to Streamline, which costs me half the price for more memory/players and a much better experience.