USED TO = A LONG TIME AGO

English has a simple method to express an event that happened long ago: used to. Hungarian, in turn, uses several adverbs of time to express such events:

régen long ago, a long time ago
azelőtt earlier, in the past
valaha once

These adverbs require the verb to be in the past tense.

Régen sokat jártunk a parkba.
We used to go to the park a lot.

Azelőtt mindig húst ettek vasárnap.
They used to eat meat for lunch on Sunday.

Valaha kívülről tudtam, hogy kell írni a japán Hiragana jeleket.
I used to know by heart how to write the Japanese Hiragana signs.

You can talk about a certain period of your life, too. Examples:

gyerek koromban when I was a child
iskolás koromban when I was a student

Gyerek koromban gyakran ettem édességet.
When I was a child, I often ate sweets.

Idős korában már nem hallott túl jól.
When he got older, his hearing was not too good.

So the scheme is:

gyerek, iskolás, felnőtt, idős…
koromban (when I was a child, a student, an adult, old)
korodban (when you were…)
korában (when he/she was…)
korunkban (when we were…)
korotokban (when you were…)
korukban (when they were…)

Of course, the noun kor (age) is fitted with the possessive endings as you see above and the suffix -ban is added.