There are several options for installing your license - either through the application interface or via FTP or SSH/SCP.
To install your license via the application, your web server (that usually means Apache) needs to have write permissions to the directory:
/path/to/browsercrm/licence/txt/
In your browser, go to http://your_browsercrm/licence
By FTP or SSH, copy the licence.txt file to the location
/path/to/browsercrm/licence/txt/licence.txt
Note that the licence.txt file is with the British English spelling of “licence”.
Ensure the file permissions are set to be readable by your web server.