Noon Sakinah: Noon Sakinah ( نۡ ) is a Noon letter with a Sukoon or a Noon without any Haraka.
Ghunnah: Ghunnah is a Nasal sound specifically produced from the Nasal Cavity. Ghunnah is produced as the air streams through the Nasal Cavity during the pronunciation of the voice of Meem (م ) or Noon (ن). It is almost like a hmm sound. If you close the opening of the Nostril you will not be able to produce the Ghunnah sound. Pinch your nose and try saying words that start with ‘m’ or ‘n’. You will feel your nose vibrate if you hold that letter.
Ghunnah duration: The ghunnah sound has an average duration of two Harakat similar to the time it takes to say one-two.

Iqlab: Iqlab means to convert something into another.

If the letter Baa ( ب ) comes after Noon Sakinah ( ن ) or Tanween the “noon sound” will be changed into Meem ( م ) and the reciter should make a Ghunnah. Simply, convert the Noon sound into a Meem sound, and pronounce the letter “Baa” afterwards.

Idgham: Idgham means to merge two letter sounds or to put something into the other.

If the letter Laam ( ل ), Raa ( ر ) comes after Noon Sakinah ( نۡ ) or Tanween, then we don’t pronounce the noon sound.
When we apply the same rule, we don’t make the Ghunnah sound.

If any of the following letters, Yaa (ى ), Meem ( م ), Waaw (و ) and Noon ( ن ) comes after Noon Sakinah or Tanween, we don’t pronounce the Noon sound, and we pronounce the following letter and lengthen them for one second with Ghunnah.
Just imitate the examples below and focus on red-colored spots while doing it.
Idghaam with Ghunnah letters however are easily remembered by the word “Yanmu / ينمو”.

Izhar: Izhar means clarification or reciting clearly.

If any of the following six throat letters comes after Noon Sakinah or Tanween, then read clearly (no sound change) without Ghunnah.

ه ,غ ,ع ,خ ,ح ,ا 

Ikhfa: Ikhfa means hiding.

If any of the following letters comes after Noon Sakinah or Tanween, then the Noon Sakinah or Tanween will be pronounced with a very light sound (slightly hide the /n/ sound) from the Nose and with Ghunnah.