My Django project structure is:
/proj
  /frontend
  /server
    /proj
    /app1
    /app2
  manage.py
How do I run python ma         
        
You can specify the path to /server/appname directory after appname as the destination i.e. where the Django app directory structure will be created.
From the startapp docs:
startapp  [destination] # startapp command usage 
 
Creates a Django app directory structure for the given app name in the current directory or the given destination.
If only the app name is given, the app directory will be created in the current working directory.
If the optional destination is provided, Django will use that existing directory rather than creating a new one
So, you can specify the path to your /server/appname directory as the destination value.
django-admin.py startapp appname [destination] # specify destination
What you need to do?
1. You need to first create a directory appname inside /server.
mkdir /server/appname # create directory from root level
2.  Then, run the startapp command to create the app.
django-admin.py startapp appname ./server/appname