Is it correct to purify oneself and perform ghusl after seeing dryness on the eleventh day? Do the brown and yellow discharges that continue after the clear red blood count as menstruation? And what are the signs of purity that should be relied upon?

Yellowish and brownish discharges are considered menstruation if they are connected to the blood at its end. So, if the bleeding stops and the woman sees a yellowish or brownish discharge connected to it, she is not purified until she sees the dryness. Upon seeing the dryness, she must perform ghusl (definition) (ritual bath), and any yellowish or brownish discharge that appears thereafter is not considered menstruation. The procedure of waiting until the eleventh day to see the dryness and then performing ghusl is the correct one.