Notice:
To say čtvrt na "něco" or třičtvrtě na "něco" could be tricky for English speaking person, think of it this way:
čtvrt na "něco" ...... a quarter to see on the Clock to "something"
třičtvrtě na "něco"... a three quarters to see on the Clock to "something"

Also it is quite common, for example, for 1:40 to say: za 5 minut třičtvrtě na dvě (in 5 minutes three quarters on the Clock to two), and all kinds of different cases, for example, 1:20, za deset minut půl druhé (in 10 minutes half of two) etc.

půl "něčeho" means half of "something" where word "of" in Czech is is expressed by changing the end of the word that follows word half (půl)
example: půl jedné = half of one , where word jedna changes to jedné

In Czech you can encounter to see Time written (and spoken) in the form of military time format , for example" 8:00pm is 20:00, it is quite common (magazines, for TV programs beginnings, etc.), and it is quite natural for Czech speaking person. There is no use of AM or PM in Czech.You will certainly never see the Clock like this one bellow, it is for training purposes only.