Turn left twice to face the device. Use the mug of water on the cauldron. Use the horseshoes, thread, stone and sand on the cauldron:

Select the green Done button at the bottom-left corner of the screen to complete the liquid. Turn left and take one of the glass retorts from the shelf. Turn right and use the glass retort on the tap to fill it with the yellow liquid. Combine the glass retort with the note from the bedroom to make the magic potion. Turn right and take the old torn boot on the floor: