While you can create an entire report on-the-fly using VBA, it might be
easier to place hidden controls for all the possible fields in your report,
and pass the names of the selected fields in the optional OpenArgs parameter
of the OpenReport method.  You can set the Visible and Left properties in the
report's On Open event.

' The code assumes that the textbox corresponding to each checkbox has the
same
' name except a different prefix, e.g., chkName/txtName.  While it has basic
' error-handling, you may wish to augment it (for example, as it's currently
' written, it will cause an "Invalid Use of Null" error if the report is
opened in any
' context than by the control button and an "Invalid Procedure Call or
argument"
' error if no fields are selected).

' Command button On Click event code
On Error GoTo Err_Handler
   
   Dim strOA As String             ' OpenArgs string
   Dim stDocName As String     ' Report name
   Dim ctl As Control                ' Control variable
   
   strOA = ""
   
   ' Loop through all controls
   ' If control name matches array element, add to OpenArgs string
   For Each ctl In Me.Controls
       If ctl.ControlType = acCheckBox Then
           If ctl.Value = True Then
               strOA = strOA & "txt" & Mid(ctl.Name, 4) & ","
           End If
       End If
   Next ctl
   
   ' Strip off last comma
   strOA = Left(strOA, Len(strOA) - 1)
 
   ' Change to the name of your report
   stDocName = "Report1"
   
   ' Open report in preview mode with optional OpenArgs parameter
   DoCmd.OpenReport stDocName, acPreview, , , , strOA

Err_Exit:
   Exit Sub

Err_Handler:
   MsgBox Err.Description
   Resume Err_Exit

' Report On Open event code
   On Error GoTo Err_Handler

   Dim astrControl() As String     ' Control name array
   Dim i As Integer                     ' Loop counter
   Dim ctl As Control                  ' Control variable
   Dim sglCurPos As Single         ' Position to place next visible control
   
   ' Horizonal offset, in twips, from one control to the next
   ' 1440 twips = 1 inch, set here to .05"
   Const cintOffset As Integer = 72

   sglCurPos = 0
   
   ' Parse OpenArgs to string array
   astrControl() = Split(Me.OpenArgs, ",")
   
   For i = 0 To UBound(astrControl)
       For Each ctl In Me.Controls
           If ctl.Name = astrControl(i) Then
               ctl.Visible = True
               
               ' Set left edge of control to sglCurPos
               ctl.Left = sglCurPos
               
               ' Increment sglCurPos
               sglCurPos = sglCurPos + ctl.Width + cintOffset

               Exit For
           End If
       Next ctl
   Next i

Err_Exit:
   Exit Sub

Err_Handler:
   MsgBox Err.Description
   Resume Err_Exit

End Sub

Hope that helps.
Sprinks

Note that you must also ensure that the total width of the selected fields
and corresponding offsets does not exceed the page width.

Sprinks