Here is a simple, step-by-step approach to making GAPS yogurt:
1. Slowly heat full fat milk (of any animal) to 180 Fahrenheit.
2. Let cool to 68-77 Fahrenheit (20-25 Celsius).
3. Add starter. Stir to completely dissolve. A hand whisk works well.
4. Pour into containers. (Canning jars work well.)
5. Cover. (Canning jar lids work well.)
6. Set into a place that brings the yogurt (not just the surrounding air) back up to, then maintaining, 95-110 F for 24-36 hours (the latter for people especially sensitive to lactose).
Equipment that may keep your yogurt sufficiently warm includes: oven with a regular lightbulb in it (be sure to remove this bulb before again using the oven as intended); box near a heat source; heating pad; dehydrator; some commercial yogurt makers plugged into a dimming extension.