Heiße is when you are talking about yourself, e.g. Ich hei<span>ße Rachael. Hei</span>ßt is when you are talking about someone else, e.g. Du hei<span>ßt Ella.
Hei</span>ße and heißt are different conjugations of the word hei<span>ßen - the end of the word changes depending on who the word is referring to. Here is the conjugation -
ich hei</span><span>ße - I am called / My name is du hei</span><span>ßt - You are called / Your name is er/sie/es hei</span><span>ßt - He/she/it is called / his/her/its name is wir hei</span><span>ßen - we are called / our name is ihr hei</span><span>ßt - you (plural) are called / your (plural) name is </span>sie hei<span>ßen - they are called / their name is </span>Sie hei<span>ßen - you (formal) are called / your (formal) name is
Das and die are different words that show the gender of the noun you are using. There is also a third word, der. 'The' becomes either der, die, or das, depending on the gender of the noun.
Der is masculine e.g. Der Hund Die is feminine e.g. Die Katze (die is also used to make something plural) Das is neuter e.g. Das Hause.
