How To Convert Collection To String

I am trying to convert a collection to a string. When I am done, it should look like String() = {"File1.Tif", "File2.Tif", "File3.tif", "MergeTiffImages.Tif}. Here is what I have so far.

Dim FileArray(0) As String
Dim Count1 As Integer
Count1 = 0
For Each k In S
ReDim Preserve FileArray(Count1)
FileArray(Count1) = """" & k & """"
Count1 = Count1 + 1
Next
FileArray(Count1) = """MergedTiffFile.Tif"""

I am getting the error "Index was outside the bounds of the array." because FileArray is a string and not an array.