Nav Computer: Centre dot on a convenient TAS (e.g. 400 kts), rotate to put wind direction (235oT) on HEADING index and mark wind on centre line 120kts below centre dot (over 280 kts).  Rotate to put heading (255oM, Variation 40oW = 215oT) next to HEADING index; slide to put groundspeed (375 kts) under wind mark and note drift: 6o left (Port).