Django's own documentation is extremely good. You can work through its tutorials to get going.

But start with a python tutorial. I don't know which is the best, but other people should be able to help you.

I would suggest this order of learning though:

1. Python 2. Django 3. App Engine

Each introduces its own elements, so you're better proceeding step by step. Obviously you don't have to master python to get going with django, but you want to be comfortable.