If you like code, try something like this. It's a loop within a loop.
Code:
Private Sub UpDate_Click()
Dim db As DAO.Database
Dim rs1 As DAO.Recordset
Dim rs2 As DAO.Recordset
Dim myCriteria As String
Set db = CurrentDb
Set rs1 = CurrentDb.OpenRecordset("SELECT * FROM tbl_Client ORDER BY ID;")
Set rs2 = CurrentDb.OpenRecordset("SELECT * FROM sql_Color ORDER BY Client_ID;")
rs1.movelast
rs1.MoveFirst
rs2.movelast
Do While Not rs1.EOF
rs2.movefirst
Do while not rs2.eof
if rs1!ID = rs2![Client ID]
rs1.edit
rs1![Color ID] = rs2![Color ID]
rs1.update
Exit DO
endif
rs2.movenext
Loop
rs1.movenext
Loop
rs1.Close: Set rs1 = Nothing
rs2.Close: Set rs2 = Nothing
db.Close: Set db = Nothing
End Sub