The Inbox is the place to store all your to-dos until you know when to do them. That way, you can just dump all your thoughts there and at a later point try to plan them into your day.
You can find the Inbox under the 📥 button at the top (on iPhone) or in the sidebar (on iPad).
Creating an Inbox task
Inbox tasks are similar to any other task, they just don't have a time and day assigned to them. You can create a new Inbox task, by tapping the ➕ button in the top-right corner of the Inbox. This will set up the task, to already be in the Inbox. You can see this, by the In Inbox in the When? section.
After you hit Create Task the task will automatically be added to your Inbox.
If you want to add an existing task to your Inbox, you can edit it and then tap the More… button, next to the When? text and select Add to Inbox. After you save the changes, the task will appear in your Inbox.
Adding a task to your day plan
Once you know when to do a task, you can add it to your day plan, by tapping the ➕ next to the title of the task. This will open the Edit window and allow you to enter a time and day for the task. After you hit Add Task, your task will be removed from the Inbox and appear in your schedule.
Import Reminders into the Inbox
If you're using Structured Pro, you can automatically import new to-dos from the Reminders app into your Inbox. From there, you can add them to your schedule, like normal tasks. To learn how to enable the Reminders integration, checkout Import Reminders into Structured.
Pro Tip: Template Tasks
Sometimes you have a task, which irregularly appears again and again. Instead of creating a new one every time, you can just create a template task in your Inbox and copy it into your day plan when you need it. To achieve that, simply create a normal task and leave it in the Inbox. Instead of using the ➕, you can tap the title and then select More. This will open another menu, where you have the option to copy a task. Here you'll have to select the Add to Day Plan button and set the time and day.
That way, the template task will stay in the Inbox and you can do this process over and over again.