In the first section you have discovered the programming environment (Visual Basic Editor and Macro Recorder). In the second section you have learned many useful VBA words (code). After these 2 sections of the tutorial on Excel macros (VBA) you can use all the macros available for free on the Internet and you can build your own.
In section 3 you will learn how to create customized dialog windows (also called userforms).
When the message box or the input box (that you have discovered in lesson 17) is not enough to communicate with the user you can create your own simple or complex dialog windows like the one below.
On this website you will find a simple exercise (starting in lesson 24 and ending in lesson 28) that will show you how to develop your first userform. The simple form that you will create (image below) will allow a user to enter a value in the first cell of a database.
Lesson 24: Userforms in VBA for Excel
Lesson 25: Userforms and Controls Properties
Lesson 26: Labels in VBA for Excel
Lesson 27: Text Boxes in VBA for Excel
Lesson 28: Command Button in VBA for Excel
Lesson 29: Combo Boxes in VBA for Excel
Lesson 30: List Boxes in VBA for Excel
Lesson 31: Check Boxes, Frames and Option Buttons
Lesson 32: Spin Buttons
Lesson 33: Image Controls