You need to find out where the files are installed and use that within the script. If you're using an automated installer then this will most likely be in an environment variable somewhere.
would change the working directory to the right place if the installation path was held in INST_PATH, by way of example.
See the installer's documentation for more details.
You could also look at the value of $0, which contains the path of the script, followed by a slash, followed by the name of the script. If you can strip off the /Bitrock.sh at the end, then this will give you the installation directory.