Hi, the instructions would depend on your type of yoghurt maker. I have a vintage kenwood yogurella electrical yogurt maker (Y.M.) with 6 jars.
Measure 800ml of your choice of milk (equivalent to 5 jars) into a pot. I use whole milk, also known as full-fat although fat is actually less than 4%.
Heat on the hob until the milk starts to climb the side.
Take off hob and allow to cool to body temp.
Stir 1 small pot of natural live yogurt into the cooled milk.
Pour into jars and place them on the base of the Y.M.
Turn Y.M on and set timer.
4-6 hrs later, delicious, homemade yogurt.
No sachets needed and you can eat them as natural yogurt or add fruit or honey to before serving.
You can also keep a jar back to use as your starter next time instead of buying another live natural yogurt. You can make six 160ml yogurts for around 60p.