From Achadinha take the local road to Salga (M521). After 2,5 Km, exit this road and take a narrow one (right side) until the parking of Miradourdo do Salto da Farinha (less than 500 m). Despite you can go further I recommend to park the car and walk 10 minutes to the viewpoint.
To go to the base of the waterfall, walk 5-10 more minutes following the path. You’ll be in a viewpoint under the waterfall.
© Picture by Ramon Roura i Grabulosa