Selection.style applied to wrong paragraph (and other issues) - vba

Question

I have multiple documents coming from the same template. Each of them starts with a chapter number, so that I can build a table of contents that includes all of them. Since chapters have sections and subsections, I created a multilevel list style called MyList. Since they are different documents and all lists would start at 1, I need to specify the chapter number manually.
This can be achieved by writing {LISTNUM MyList \l 1 \s x} on the first line, x being chapter number. I wrote a macro to prompt for the chapter number, insert a carriage return and apply a new paragraph style to type the chapter name:
Chapter 1 (style: ChapNum)
Chapter name here (style: ChapName)
Normal text blah blah
The (working) code I have right now is:
Sub ChapterNumber()
Selection.Style = ActiveDocument.Styles("ChapNum")
ActiveWindow.View.ShowFieldCodes = True
Num = InputBox("Chapter number", "Random title")
SendKeys "^{F9}"
Selection.InsertBefore Text:="LISTNUM MyList \l 1 \s " + Num
SendKeys "%{F9}{RIGHT}{ENTER}"
End Sub
I have encountered a few issues until I finally got there, which are:
I was unable to apply a different paragraph style after the last Sendkeys using Selection.Style = ActiveDocument.Styles("ChapName") since the whole thing converted to ChapName style, not only the paragraph where the cursor was pointing.
I've read Sendkeys is not that reliable so, initially, instead of SendKeys "%{F9}{RIGHT}{ENTER}", I tried
ActiveWindow.View.ShowFieldCodes = False
Selection.EndKey Unit:=wdLine
Sendkeys "{ENTER}"
Neither of the first two commands worked, and I don't know why; I have used them in other macros and never had any problem. Would you please be so kind to clarify? Please take in mind my knowledge of vba is very limited.
Thank you.

Answer 1

Add the text "Chapter " to your template and apply the correct style. Add empty paragraphs in the other two required styles and your template is already setup for you to start typing. All that is then required is to add the LISTNUM field which can be done as shown below.
Sub ChapterNumber()
Dim Num As Long
Num = InputBox("Chapter number", "Random title")
Dim location As Range
With ActiveDocument
Set location = .Paragraphs(1).Range.Characters.Last
location.Move wdCharacter, -1
.Fields.Add Range:=location, Text:="LISTNUM MyList \l 1 \s " & Num
End With
End Sub
EDIT IN RESPONSE TO COMMENTS:
As you appear to have defined numbered styles in your template you do need to add the LISTNUM field. Instead you should set the start at number for the list template attached to the style.
Sub ChapterNumber()
Dim Num As Long
Num = InputBox("Chapter number", "Random title")
ActiveDocument.Styles("ChapNum").ListTemplate.ListLevels(2).StartAt = Num
End Sub