The easiest way to run a command in Minecraft is within the chat window. The game control to open the chat window depends on the version of Minecraft:For Java Edition (PC/Mac), press the T key to open the chat window. For Pocket Edition (PE), tap on the chat button at the top ...
so you don't need to worry about the path. DOS and some other systems allow relative paths that start with a drive prefix. For example, C:foo.exe refers to foo.exe in the current directory on drive C, so you should look up the current directory on C: and use that...