The Vipassana Strong Determination.
A thought in my mind is to set the rules for the vipassana is arising, I will go there tomorrow and it will last for the next 10 days.
The first simple rule is to eat the amount that is just enough for the survival of the body, not for the mind, be mindful when you are taking the meal and take less if you need more go and take it in the next round. Never take twice because of the taste.
For the sitting, there are 3 sittings, first two hours and then 3 hours and then 4 hours, and then last one for one hours and so on. I have done 3 and 4 hours before, make sure you go the toilet before sitting, and only get out if you are feeling excessive urination.
In this period you will feel the mental challenge of different impulsive need to break this rule, but It is doable, I have done before, and people like goggins have done it on the crazy level. observe this rule. In between sleep and rest.
For the time being, release yourself from any kind of thought and experimentation and completely do what gonika ji is asking you to do.
First three days, put your entire effort to observe the sensation around your nose, including the time of sleeping and resting.
Then for the vipassana observe the sensations with equanimity and the understanding of impermanence. Day in and day out.
Keep your eyes down and do this nothing else, absolutely nothing else. You know the mind and how it plays the games, at the best there will be some physical unease and mental tension which passes away soon anyway.
Make the strong determination to this retreat with utmost sincerity.