How to distinguish between partitive articles du, de la, de l' ,des and FROM.

Bonjour Zubair !

That's a very good remark, and it works for the partitive articles (some), for "from the", but also "of the" which are both expressed with "DE + definite article" in French.
The answer I can give you is that context is the only way to differenciate them.

Here are some examples to practice :)
1- Je mange du pain. (I eat [some] bread. -> partitive)
2- J'ai sauté du bateau.  (I jumped from the boat.)
3- J'aime la sœur du facteur.   (I love the postman's sister -> the sister of the postman)

I hope that's helpful!
À bientôt !