If you want to be able to read as well as understand basic Arabic texts, you need to acquire some basic vocabulary. Basic communication phrases to express your gratitude, hospitality and some different forms of greeting would greatly help you in your journey to learn Arabic. Although self-learning is a good first step to learn Arabic, it is always preferable to seek guidance in order to learn properly.
Check out this magazine in Nour Academy it has many articles about learning Arabic and Quran.
Basically the Noon Sakinah is a Noon (ن) devoid of any vowels; namely the Kasra (كسرة), fatha (فتحة), and dammah (ضمة). In the Quran, the noon Sakinah can be depicted with a Sukoon (سكون) above it or without anything above it at all like this (ن). It is important to note that both have the same pronunciation and are called Noon Sakinah.
But the tanween is an extra Noon Sakinah used with the Kasra (كسرة), fatha (فتحة), and dammah (ضمة).
If you are interested to listen to the pronunciation of the noon sakinah and tanween take a moment to read this article: Learn to read Quran with Tajweed Rules: Noon Sakinah and Tanween
Hamza does not originally belong to the original 28 Arabic letters. It is, however, derived from the Arabic letter Aein (ع). It is most often seen atop or below the letter.
But it is still considered one of the main vowels in the Arabic language.
If you want to know more about the Hamza and its forms, try to check on this article Learn Arabic Letters and Diacritics: Al-Hamza