Al = A + el
When saying a el, it’s hard to pronounce due to the double vowel so in Spanish we just shorten it and say al. Al is generally used to say “to the” or “at the” e.g. i go to the park = voy al parque, or i will wait for you at the end of the street = te espero al final de la calle.
Del = de + el
Same here for del, when saying de el, it’s also hard due to the double e vowel and so it’s again shortened to del. Del is used when saying something belongs to someone or someplace. e.g., the boy’s car = el coche/el carro del chico. (In this sense, only the person that the object belongs to is masculine the object can be feminine or masculine but if it was the girl’s car, it would be el coche/el carro de la chica and here you don’t shorten de la since there is no double vowel). As well you can say a person or object is from a place, e.g., I’m from the north of Denmark = soy del norte de dinamarca.
I hope this helps! :))