A relative has a wordpress based site that they want me to make a few changes to that I can't seem to find a way of doing from wordpress itself because it puts everything in categories but if something doesn't install itself fully or anything you can't find all the files. I want to have some kind of file manager so i can browse the website's filesystem directly, find the files and add the exact code I want to add, and be done with it without removing or disabling wordpress itself.
Use and ftp client to login. This will allow you to browse the file and folder structure of the server. Once you get logged in you can use......
dir - directory listing cd - change directories put add files to the server get - pull copies of files from the server
There's more, but this should get you started.