てからでないと
te kara de nai to
not until after; unless done first
[Not until after / Unless (something is done) first]
Connection: Verb (て form) + からでないと / からでなければ
Usage: Expresses that something cannot be done or is not possible unless a prior action is completed first. Emphasizes the prerequisite nature of the first action.
Examples:
説明書を読んでからでないと、この機械は使えない。(You can't use this machine until after you've read the manual.)
実際に住んでみてからでないと、その町の良さはわからない。(You won't understand the appeal of the town until after you've actually lived there.)
予約してからでなければ、入れないレストランだ。(It's a restaurant you can't get into unless you've made a reservation first.)