If you are a very early user, you might still be using Mintter. You need to migrate your Mintter Account to your Seed Account. These are the steps:

Download the new Seed App.
Download the new Seed App. Remember, we are open source, and you can read the code and contribute in our GitHub repository. :)
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Create a brand new Seed account.
You need to create a new Seed account. Actually, you can create all the accounts you want! Unfortunately, your Mintter account will not be the same so you can throw away your Mintter Keys, but you can use the same mnemonics in Seed if you want.
Export your documents from Mintter.
We have an export button in the Mintter app. It will export all your documents to Markdown. You can run both apps at the same time. Although, the Mintter app consumes a lot of resources so don't keep it open for a long time.
Import your Markdown files to Seed Hypermedia.
You can import your files one-by-one or a whole folder into Seed desktop app.