Quick answer
Н н is the n of “no”. Russian has no h letter at all — the nearest sound is Х х.
Нн
Нн
n
нетno
How to say it
The English n, but articulated slightly further forward, with the tongue against the teeth rather than the ridge behind them.
нетno
но́выйnew
но́чьnight
ресторанrestaurant
оди́нone
наon
Н, П and И
Three letters share the same two uprights: Н has a crossbar in the middle, П a lid on top, И a diagonal. Reading a sign letter by letter once is enough to fix the difference for good.
The н- of него́
After a preposition the pronouns его́, её, их grow an н-: у него́, у неё, у них. The letter Н is doing real grammatical work there, not just sitting in a word.
Typical mistakes
Reading нет as “het”
“nyet”
Н is n.
Confusing Н with П on signs
crossbar = Н, lid = П
ПОЧТА and НОЧЬ differ by that one line.
Check yourself
Which word contains Н?
нет — no.