Twenty past
والثلث

Half past
والنصف

To say ’to’ in Arabic, we use ‘إلا which comes after the hour, so ‘quarter to three’ in Arabic would literally be ‘three o’clock less a quarter’ الساعة الثالثة إلا الربع

To
إلا

Five to
إلا خمس دقائق

Ten to
إلا عشر دقائق

Quarter to
إلا الربع

Twenty to
إلا الثلث

NOTE
We don't use neither the a.m./p.m. system nor the 24-hour military clock, when giving the time, you need to specify the time of day by actually saying what part of the day it is.

Here are the different times of day you’re likely to use:

الصباح
(morning, from sunrise to 11:59 a.m.)