To make a potion, step to the table and press Shift. Then, you will able to select a potion for the list and play a mini-game to make the ingredients. Once the recipe is complete, the new potion is added to your Potions Pouch.
Press ESC to return to the Gypsy Cart when finished.
Some gypsies don't have a Potion Table, such as Heartless Rosaline.