Config files can be added via Clanforge. Just click on edit Profile -> Configs -> Upload File
This will then add the file to the dropdown list within the Configs section.
Select the file you have just uploaded and remove any instances of the word rcon from the start of the commands as these are not supported within the context of a config file on Clanforge.
You can then execute the config file from any of the following methods:
Use the clanforge console and enter the command: exec serverid/configfilename.cfg
Using the in game console, type: exec serverid/configfilename.cfg
Note: Your server ID can be found on Clanforge. It is clearly labelled "Server ID: 1234567"