Thanks !should've auto detected but if not just go into the /game folder and copy the save folder and paste it into the /game folder for the next week
I found out why the Week2 game didn't detect my Week1 save :
I'm on Windows, and the default save folder of the Week1 game is in:
<C:\Users\USERNAME\AppData\Roaming\RenPy\Ecchi Sensei>
Whereas the default save folder of the Week2 game is in:
<C:\Users\USERNAME\AppData\Roaming\RenPy\Ecchi_Sensei>.
I don't know if it's normal or not (my Week1 and Week2 are DM patched)
Moreover, i got another folder :
<C:\Users\USERNAME\AppData\Roaming\RenPy\Ecchi Sensei 2019>
Anyone here could explain why there are 3 different folders ?