Merging PDF docs through VBA

I have code I am using to merge 2 different PDF's, if "gPDDoc1" has 1 page and "GpDDoc2" has 20 pages. I am not familiar with the page ordering of my resulting merged PDF:

mergefile = gPDDoc1.InsertPages(1, gPDDoc2, 0, 1, 0)

Full code here:

Sub Merge()

Dim gPDDoc1 As AcroPDDoc
Dim gPDDoc2 As AcroPDDoc
'Dim gPDDOC3 As AcroPDDoc

Set gPDDoc1 = CreateObject("AcroExch.PDDoc")
Set gPDDoc2 = CreateObject("AcroExch.PDDoc")
'Set gPDDOC3 = CreateObject("AcroExch.PDDoc")

chk1 = gPDDoc1.Open("S:\FOLDER1\Title Page.pdf")
chk2 = gPDDoc2.Open("S:\FOLDER2\Full Doc.pdf")
'chk3 = gPDDOC3.Open("C:\test\test3.pdf")

mergefile = gPDDoc1.InsertPages(1, gPDDoc2, 0, 1, 0)
'mergefile = gPDDoc1.InsertPages(1, gPDDOC3, 0, 1, 0)

savemergefile = gPDDoc1.Save(1, "S:\FINALFolder\MERGED.pdf")
End Sub