This is the 3rd most frequent Russian word.
с
The Russian word "с" means "with" or "from" depending on context.
'с' here introduces the activity or event with which something begins or is associated.
Он начал свой день с зарядки.
He started his day with exercise.
In this case, 'с' denotes the circumstances or conditions under which the action takes place.
С первыми лучами солнца мы отправились в путь.
With the first rays of sun, we set out on our journey.
In this sentence, 'с' indicates accompaniment, showing togetherness or association with someone.