After selecting the version type on the configuration page (affects version, fixVersion, or your special version), it displays the bundles associated with the component and version pair in the issue next to the respective custom field. It also searches for the versions of these bundles and includes them in the display.
Adding custom fields to Jira is already well documented in Jira's own user manuals so it will not be duplicated here. One thing you should notice is, calculated fields are not available on issue update screens, they are only visible on view issue screen or as a column in issue navigator. So "Fixed in Bundle" and "Affects Bundle" fields are not available on issue create or edit screens.
Clicking on it will open issue navigator with issues fixed in bundle and/or issues affecting the bundle
