The search function is more or less global and is found under , , (and a few other places where you hardly ever need it).
You search by pressing the button in the left menu under the relevant main menu; for instance . Now you can search in all fields, several combined or just one, with any text. You search in the blue fields on the row with the (Find) button as shown below.
You can search for almost any data like mobile phone number, street address or e-mail under the dedicated fields but for this example we will search by name.
As stated above you use the blue line when searching. Enter the entire name or parts of it. We fill in 'John' in the first name field but as we are not sure how to spell 'Moxley' we will only enter part of the name 'mo'.
And hit 'Enter' or click on to see the result(s).
Mark the appropriate line (in this case 'John Moxley') by clicking anywhere on that line in order to mark it with the dark blue frame.
Click on the button in order to open up the Person page with John Moxley in focus.
Doubleclick on the hash tag and you can type in the customer number directly in the now open field.
Hit Enter and you get the person in focus.