Hello,
If I understand correctly, you want to input a customer and as soon as you Tab off the customer the rest of the fields populate with that customers information (Number, Address, Email).
There are different ways to achieve this, one way would be to add 'Text Change' actions to the customers field.
Within the 'Text Change' event we will have multiple Retrieve Value From Table actions, that will retrieve the customers data and update a field(s) on screen with that information. Here is how it will look like:
Which finds the Email of the customer and will match the customer by RecordID, then lastly update the Email field on screen with that information.
Following this format you can have multiple Actions listed (in my case I only have Email and Phone):
I hope this is what you were trying to accomplish, if not let me know and we take a further look into it together.
-- Mortaza