I've already found the relevant materials. Sharing them with everyone as well.
How to use msgbox
Description
Displays a message in a dialog box, waits for the user to click a button, and returns a value indicating which button the user clicked.
Syntax
MsgBox(prompt[, buttons][, title][, helpfile, context])
The MsgBox function syntax has the following parameters:
Parameter Description
prompt A string expression displayed as the message in the dialog box. The maximum length of prompt is about 1024 characters, depending on the width of the characters used. If prompt contains multiple lines, the lines can be separated with a carriage return (Chr(13)), a line feed (Chr(10)), or a carriage return/line feed combination (Chr(13) & Chr(10)).
buttons A numeric expression that is the sum of values specifying the number and type of buttons to display, the icon style to use, the identity of the default button, and the message box modality. For the values, see the "Settings" section. If omitted, the default value for buttons is 0.
title A string expression displayed in the title bar of the dialog box. If title is omitted, the application name is displayed in the title bar.
helpfile A string expression identifying the help file used to provide context-sensitive Help for the dialog box. If helpfile is provided, context must also be provided. Not available on 16-bit system platforms.
context A numeric expression identifying the Help context number assigned to a help topic by the help file author. If context is provided, helpfile must also be provided. Not available on 16-bit system platforms.
Settings
The buttons argument can have the following values:
Constant Value Description
vbOKOnly 0 Displays the OK button only.
vbOKCancel 1 Displays OK and Cancel buttons.
vbAbortRetryIgnore 2 Displays Abort, Retry, and Ignore buttons.
vbYesNoCancel 3 Displays Yes, No, and Cancel buttons.
vbYesNo 4 Displays Yes and No buttons.
vbRetryCancel 5 Displays Retry and Cancel buttons.
vbCritical 16 Displays the Critical Message icon.
vbQuestion 32 Displays the Warning Query icon.
vbExclamation 48 Displays the Warning Message icon.
vbInformation 64 Displays the Information Message icon.
vbDefaultButton1 0 The first button is the default.
vbDefaultButton2 256 The second button is the default.
vbDefaultButton3 512 The third button is the default.
vbDefaultButton4 768 The fourth button is the default.
vbApplicationModal 0 Application modal: the user must respond to the message box before continuing work in the current application.
vbSystemModal 4096 System modal: all applications are suspended until the user responds to the message box.
The first group of values (0 - 5) describes the type and number of buttons displayed in the dialog box; the second group of values (16, 32, 48, 64) describes the icon style; the third group of values (0, 256, 512) determines the default button; and the fourth group of values (0, 4096) determines the message box modality. When adding these numbers to generate the value of the buttons argument, only one number may be taken from each group.
Return values
The MsgBox function has the following return values:
Constant Value Button
vbOK 1 OK
vbCancel 2 Cancel
vbAbort 3 Abort
vbRetry 4 Retry
vbIgnore 5 Ignore
vbYes 6 Yes
vbNo 7 No