There is a huge amount of information about this subject in here; just scrolling down a bit you can find this topic...
https://forum.atlas-games.com/t/introducing-new-players/11763/1
...with some resources and advice on the matter.
Me personally, trying to be over newbies, explaining all I can, asking them to spend some time reading their magi's HoH chapters and some rules, and letting them adjust their magi during the first sessions. One good idea is to meet with each one of them alone for a session to work on their magi, doing examples of spells, rolls and so, and maybe having them play a short story (something simple like gathering vis or, when they are in a new spring covenant, doing some work for it), so they can start to get used to the rules and the setting.