Two different instructions- which one is correct?!

So there are two different instructions to follow and I don’t know which one is correct;

On the back of the starter packet it says once milk is cooled/warm to touch you add the sachet and mix and then incubate straight away

But on the leaflet it says once milk is cooled/warm to touch add the sachet and stir and leave for a further 15-30 and after that you incubate.

I’m using whole milk and I’m using the kefir starter culture.

Very confusing!

They are both correct if you use an electric maker or any yoghurt maker.
If you follow the traditional method, please cool down the milk to lukewarm>add the starter,stir, then allow 30 min, stir again and incubate. Please make sure that you can keep the temperature stable for the next 12-20 hours or until set. You can add a bottle of hot water next to the container with the yoghurt mix and wrap this in thick blanket, towel or something similar.