Update datatransfer.md

Adding language so that users know they need to have set up a user account and completed onboarding prior to being able to use the data transfer methods. This is the result of a virtual office hours encounter with a researcher who came directly from perusing our Published data and wanted to download a large dataset that we direct them to this section of the user guide  - so they didn't have a user account yet - and then once they got the user account they didn't know to Onboard.

Author: cockerilltim

user-guide/managingdata/datatransfer.md

@@ -7,8 +7,11 @@ DesignSafe supports multiple ways of moving data in and out of the Data Depot, a
 
 This document provides a brief description of the various methods available for moving data to and from DesignSafe to assist you in identifying the right data transfer method for your research needs. Once you have selected your data transfer method, each description concludes with a link to detailed instructions for initiating your transfer. File paths and host names are needed when using any of the data transfer methods that are external to the Data Depot's web-based transfers, with guidance found in the [Setting File Paths for DesignSafe](/user-guide/managingdata/datatransfer/#setting-file-paths-for-designsafe) section of this user guide.
 
+
 ## Recommended Data Transfer Methods { #recommended }
 
+A prerequiite to using these Data Transfer Methods is to have completed the Getting Started steps of [User Account Registration](/user-guide/#user-account-registration){target="_blank"} and [Initial Onboarding](/user-guide/#initial-onboarding){target="_blank"}.
+
 ### Recommended LARGE Data Transfer Methods { #recommended-largedatatransfer }
 
 We define a "**large**" data transfer here as any file transfer that is  > 2GB upload or > 5GB download, or > 25 files or > 2 folders.