The easiest way to get started is in the Runbox Webmail, which you can log into at https://runbox.com.
Once you have logged in, you will find a menu at the top of the page which lets you easily access the main sections of Runbox: Webmail, Manager, Contacts, Files, and Account.
To the left you will see the standard Runbox folders: Drafts, Inbox, Sent, Spam, and Trash.
You can of course add as many as you like — just write the name in the field below the folder list and click Create.
A new folder will always be created inside the currently selected folder. To create a folder at the top level, first click your email address at the top of the folder list.
To send an email, click Compose in the Webmail menu above. Just enter an email address in the To field and a subject in the Subject field, and click Send.
If you click Preferences in the Webmail menu, you will be able to change how many messages to be displayed per page, date and time format, and many other things. Note that each Webmail folder can have its own set of preferences, which makes it possible to set up several identities or profiles tied to your folders.