Sati is a factor of concentration. Sati means remembering.
Yonisomanasikara is a factor of wisdom. It means thoroughly examining.
For example, you read or hear Dhamma Teachings. The teachings say you should thoroughly examine & think about the teachings after hearing the teachings. This thoroughly examining & thinking about the teachings is yonisomanasikara.
Then when the teachings are understood, you continuously remember to keep the teachings in mind so you can continuously practise the teachings. This continuously remembering to keep the teachings in mind & to not be forgetful of the teachings is sati (mindfulness).
Thus associating with good persons, becoming full, fills up hearing
the good Dhamma. Hearing the good Dhamma, becoming full, fills up
faith. Faith, becoming full, fills up careful attention (yoniso
manasikārā). Careful attention, becoming full, fills up mindfulness
and clear comprehension. Mindfulness (sati) and clear comprehension, becoming
full, fill up restraint of the sense faculties. Restraint of the sense
faculties, becoming full, fills up the three kinds of good conduct.
The three kinds of good conduct, becoming full, fill up the four
establishments of mindfulness. The four establishments of mindfulness,
becoming full, fill up the seven factors of enlightenment. The seven
factors of enlightenment, becoming full, fill up true knowledge and
liberation. Thus there is nutriment for true knowledge and liberation,
and in this way they become full.