This members-only tutorial provides the steps to define a custom function that returns data of the current logged in user like first name, last name, display name depending on the input parameter in Oxygen.
Once the function has been added, to show user's first name for example you could simply add a Text component in Oxygen, double click to select the text, click on Insert Data button in the top toolbar, click on PHP Function Return Value and
Function Name: wpdd_current_user
Here are the possible arguments:
user_login: Username
user_email: User email
user_firstname: User first name
user_lastname: User last name
display_name: User display name
ID: User ID
How to add the Function
Install and activate Code Snippets plugin.
Go to Snippets > Add New.
Title: [Function] Current User Info
Code: