@anusvAra letter

Every letter in written Sanskrit has always the same sound, except the anusvAra letter and the visarga letter.

When pAnini says /anusvAra in a sUtra, that means a hum sound.

The anusvAra letter M ं is to be pronounced as a hum sound whenever it is before h ह् y य् r र् v व् l ल् z श् S ष् s स्, and only there —

ayodhyAM yAti ← always pronounce this as "ayodhyA + hum + yAti "

Whenever the M ं letter appears in front of one of the 25 stops and nasals, it is just a weird way of spelling one of the sounds J ञ् m म् G ङ् N ण् n न् (see anusvArasy...) —

tam pazyati तं पश्यति ← always pronounce this as "tampazyati"

Whenever you find an M ं letter elsewhere, that is, before a vowel or before a pause, it is a lazy spelling for the ordinary m म् sound —

pazyati taM | पश्यति तं । ← pronounce (and spell!) this as pazyati tam | पश्यति तम्।