I'm trying to follow some instructions with the first line:
1) Set the "query field" (Account Name in getUserProfileByName Secondary Recieve data source) to the Account Id of field selected in People Picker.
From here. But when I go try and edit queryfields it's greyed out? Ultimately I'm trying to populate fields when a user selects a user from a People Picker. Any help appreciated.
I'm using InfoPath 2013.

To autocomplete this you'll have to use a support or population-related field, with a new action rule. This is due to people picker fields not allowing any action rules applied to them.
Condition:
Actions:
Please note: getUserProfileByName / User Profile Service Data Connection no longer works in SharePoint Online and results in an error 5566. Please use a SharePoint list data connection to the hidden User Information List on the stem of your SharePoint site instead. It provides you with most of the same fields you'd find in getUserProfileByName, see below:
Hope that helps!