Concatenating data from two cells and importing data from other sheets?

I am attempting to read data from a separate sheet into the main excel sheet. Also I need to read in different cells from different sheets and combine them into one cell in my main sheet.

If someone knows how to do this and wouldn't mind showing me an example I'd appreciate it.

At the very least show me a good link so I can teach myself.

Private Sub UserForm1_Initialize()

    txtComment.Value = ""
    txtNetwork.Value = ""

End Sub

Private Sub CommandButton1_Click()

    ActiveWorkbook.Sheets("Main").Activate
    Range("A1").Select
    
    ActiveCell = txtComment.Value
   ActiveCell.Offset(0, 2) = Inputs!A1.Value
   

End Sub

EDIT: The final line of code says 'object required.' Inputs is one of my worksheets and there is a value in A1 so what is the problem?

Thanks in advance.