The easiest way to restore all of your accounts is to make sure each account has some SOL in it so that Phantom can detect it. Follow these steps and let me know if your issue is resolved:
- Make sure your Secret Recovery Phrase is written down correctly and backed up
- Send a little SOL to each account you would like to restore
- Go into Settings, scroll down and click the red button that says "Reset Secret Recovery Phrase"
- Re-import your wallet using your Secret Recovery Phrase
- All of you accounts should be detected and available through Phantom again
In a future release we will be adding some functionality to make this process a lot better and Phantom will be much smarter at detecting your wallets. I hope this helps!