自 indicates the place from where an action started. Sometimes it may be omitted when translating into English.
In a sentence we should state 自 before a noun that denotes a place.
We leave from Beijing tomorrow
wǒmen míngtiān zì běijīng chūfā
To down the stairs
zì tīzi diēluò
We often use 自 in the construction 自…到… .
The passengers take a taxi from the airport to the hotel
lǚkè zì jīchǎng gǎi chéng chūzūqìchē dào lǚguǎn
The meaning “starting from”
Sometimes 自 can be used to express the starting point of an action in the past. It can be translated as “ever since/since”.
After expressing the time, we should use the following words:
后 or 以后 起 or 开始 以来
We can state the subject before 自 or after the adverbial modifier of time.
Since last year, our problems have gotten bigger
zì qùnián yǐlái, wǒmen de wèntí biàn dà le
She has come back to life much more vigorously since her reply
tā zì huífù yǐhòu huó de gèng yǒujìn le
In this meaning, we also can use 自 in the construction 自…到….