Hi All

Please can someone help me understand the following code.

I needed to collate all sheets onto one sheet to pivot data from it. I found this code online and it works perfectly however I don't understand why it does and hope someone here can explain it in very basic and simple terms to someone who knows very little about coding:

In the below code:
Line 1 - where does "J" come from, what is that? Why is it J?
Line 2 - what does "On error Resume Next" mean?

I do follow lines 3 - 5

Line 6 - I have no sheet called "Sheets(2)" so what is this doing?

Line 8 - same question there is nothing called "Sheets(1)" so how does this reference work?

Line 9 - hopefully will be answered above but what is "J". Why equal "2"?

Sub Combine()
 1 Dim J As Integer
 2 On Error Resume Next
 3 Sheets(1).Select
 4 Worksheets.Add
 5 Sheets(1).Name = "Combined"
 6 Sheets(2).Activate
 7 Range("A1").EntireRow.Select
 8 Selection.Copy Destination:=Sheets(1).Range("A1")
 9 For J = 2 To Sheets.Count
 10 Sheets(J).Activate
 11 Range("A1").Select
 12 Selection.CurrentRegion.Select
 13 Selection.Offset(1, 0).Resize(Selection.Rows.Count - 1).Select
 14 Selection.Copy Destination:=Sheets(1).Range("A65536").End(xlUp)(2)
Next
End Sub
The code does work however I am needing to do a lot more in vba and am still clearly battling with the basics.

I am going through this website and this https://powerspreadsheets.com/vba-sub-procedures/ which seems pretty good however as often happens, I need to actually be creating the sheets and not learning about them so any assistance in speeding up the process would be highly appreciated.

Thank you