Is there somewhere where I can find more information about how the "transfer" recruiting works?

Players at the end of the season may opt to transfer. Some players also leave early. This frees up scholarships for teams. This means that some teams will still have leftover scholarships after the season flip prior to signing day where they can go in and offers scholarships to remaining players and transfers from other schools. It works the same way... you add recruiting points and offer remaining scholarships from the recruiting screen.