Clarify process for transferring existing research repos

docs/jobs-site.md

@@ -2,7 +2,12 @@ The [jobs site](https://jobs.opensafely.org/) is where you can run your code on
 
 ## Jobs site structure
 
-The jobs site is centred around **Projects**. When an application to run a study in OpenSAFELY is [approved by the data controller](https://www.opensafely.org/onboarding-new-users/), a _Project_ is automatically created. You can see a [list of approved projects, and the organisation they belong to](https://www.opensafely.org/approved-projects/). We will add any GitHub usernames listed in your approval to our `opensafely` [GitHub organisation](https://github.com/opensafely). We also will transfer your existing OpenSAFELY study repository (if you have one) into the same organisation. This allows OpenSAFELY to enforce certain security standards, such as [multi-factor authentication](https://docs.github.com/en/github/authenticating-to-github/securing-your-account-with-two-factor-authentication-2fa).
+The jobs site is centred around **Projects**. When an application to run a study in OpenSAFELY is [approved by the data controller](https://www.opensafely.org/onboarding-new-users/), a _Project_ is automatically created. You can see a [list of approved projects, and the organisation they belong to](https://www.opensafely.org/approved-projects/).
+
+We will add any GitHub usernames listed in your approval to our `opensafely` [GitHub organisation](https://github.com/opensafely). We will also ask you to [transfer](https://docs.github.com/en/repositories/creating-and-managing-repositories/transferring-a-repository) your existing OpenSAFELY study repository (if you have one) into the same organisation. This allows OpenSAFELY to enforce certain security standards, such as [multi-factor authentication](https://docs.github.com/en/github/authenticating-to-github/securing-your-account-with-two-factor-authentication-2fa).
+
+!!! warning
+    It is important that the study repository is _transferred_ into the `opensafely` organization, not _forked_ into it. Please [ask us](how-to-get-help.md#slack) if you have any problems with this process.
 
 Within each _Project_, there are one or more **Workspaces**, which are linked to a GitHub repository in the [OpenSAFELY organisation](https://github.com/opensafely). Any [actions](actions-intro.md) you develop as part of your [project pipeline](actions-pipelines.md) within the attached repository are linked to the workspace, allowing these to be run against real data.