First of all you have to follow the instruction here.

After that, download the source code of tinyMCE, unzip, grab the ‘tiny_mce’ folder, inside the ‘jscripts’ folder, and put it in the media folder of your project. Ex.:

$ unzip tinymce_3_*.zip
$ cp -r tinymce/jscripts/tiny_mce your_media_project_path/tiny_mce

To turn on the wysiwyg on the admin page you need to include the main tiny_mce javascript file and the javascript that convert the textareas on the admin page.
It’ really simple. Open your admin model and add the Meta class with js paths. Ex: of your app
from yourproject.yourapp.models import YourModel
from django.contrib import admin
from django.conf import settings

class YourModelAdmin(admin.ModelAdmin):
    class Media:
        js = (settings.MEDIA_URL+'tiny_mce/tiny_mce_src.js',

Now you can put whatever you want on your contents!