I am trying to customize the default UI of open edX. But I am not getting far enough. I am new to this. I am getting confused reading the docs. In the documentation it is telling me to place my theme in the '/opt/bitnami/edx/var/themes/edx-platform' directory. But there is not any such directory. So should I make my own directory in the default location of my remote server? Again I found a directory that has path like this '/opt/bitnami/edx/app/edxapp/edx-platform/themes'. So do I put my custom theme here or create my own directory? Also can anyone provide me clear steps which I can follow. Thanks in advance!