How to use a different email address in journey builder?

The scenario we have is that we are storing email address information in other different data extensions. So it depends on the journey whether we use these or the primary email address (stored in all subscribers list). However, journey builder only uses the all subscribers list email address even if we set the Journey Builder Settings to > Use Primary Email Address from data extension; Use Email Address from Entry Source Only.

Custom Profile center code along with admin page in sfmc documentation clarification?

Please refer to this post Build a Custom Profile Center for Multi-Org purpose and then to this link in the sfmc documentation:https://developer.salesforce.com/docs/atlas.en-us.mc-apis.meta/mc-apis/creating_a_custom_profile_center_using_ampscript_and_the_soap_api.htm. I’m sure a lot of you are familiar with these two docs.