You should adhere to the 8 precepts during retreat
https://en.wikipedia.org/wiki/Eight_precepts
1. I undertake [to observe] the rule of abstinence from taking life - no kill, even mosquitoes...
2. I undertake [to observe] the rule of abstinence from taking what is not given - no theft
3. I undertake [to observe] the rule of abstinence from unchastity - no sex
4. I undertake [to observe] the rule of abstinence from false speech - no lie
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5. I undertake [to observe] the rule of abstinence from intoxicants which cause a careless frame of mind - no drugs
6. I undertake [to observe] the rule of abstinence from taking food at the wrong time - no eating from pm to dawn
7. I undertake [to observe] the rule of abstinence from dancing, music, visiting shows, flowers, make-up, the wearing of ornaments and decorations
8. I undertake [to observe] the rule of abstinence from a tall, high sleeping place. - just wood bed, straw mat
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It's a serious and demanding exercice especially as
* It has a high level of discipline. when joining, you are asked to agree to the whole schedule and follow it.
* You lose control of schedule and most of sense of time as sessions are all part of required assignment delimited by bell ringing (big one for start, smaller for end). Imho, this is similar to middle-high school and results in feeling time flowing slowly (compare to the rest which mostly feels always running).
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* 4am-9pm schedule with only 2 vegetarian meals per day.
* Monastic environment: quiet and peaceful but also very basic comfort (wood bed, thin straw mat, wood pillow, bucket shower, hand laundry...).
* Total disconnect, from Internet but more, all electronics devices, reading, writing, or more simply any communication with any other participants during retreat time (ok on registration day and when leaving)
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The reason for all this is focus. With 4 times a day a sequence of sitting meditation, yoga (early morning only) or walking meditation, and sitting meditation again for 2-3h, you are bound to up your meditation.
While some guidance is given on meditation and buddhism, "mindfulness with breathing" depends mostly on each individual own understanding of his/her/their breathings and body.
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Even with that, there is still a "time to enter/exit" retreat: where you ask yourself, should I give up aka leave retreat early. or at the end, end is coming, what's next. While all normal human reaction, it will hinder our capacity to make our mind focused. If possible, better to have those choices before or after retreat time.
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On silence, outside of staff communication (partly done via whiteboard) and chanting, you won't hear anything except nature "silence" (birds, insect... occasional remote train or plane).
If not used to regular meditation or not fit enough, you may have some tensions or pains due to pace. or simply because of monastic environment. If tolerable, patience is key and body will adapt with time.
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Intro: don't expect anything, observe, experiment
Conclusion: if expect enlightenment, enroll as monk/nun. Continue regular practice.
imho, it also need time to "digest" or slow down like the time following any intense work or event.
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As more an early bird, my best time was the early morning session (4.30am-8am) including first sitting meditation, yoga, second sitting meditation with sunrise in background.
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My two side enjoyments
* Hot spring bath (natural) - men/women separated
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