Set Up Django Debug Toolbar to Find Slow Queries

I want to find slow database queries in my Django app before users complain.

Set up Django Debug Toolbar so I can:
- See every SQL query each page runs
- See how long each query takes
- Spot queries doing full table scans (sequential scans)
- Identify which queries would benefit from an index

Walk me through the installation, settings, and what to look for once it's running.

My Django version: [your version, e.g. Django 4.2]

I'm learning, so explain each part simply.