yesterday--ayer
last night -- anoche
for "last", use the adjective "pasado"
or "pasada" ALWAYS SINGULAR: El fin de semana pasado.
La semana pasada.
Or, use the adjective "último-última" ALWAYS SINGULAR:
El último fin de semana. La última semana.
If you want the plural, which in English corresponds to structures
that include the word "ago", there is an important
syntactical structure based on the verb "hacer":
Two weeks ago--- hace dos semanas.
PASADO DOES NOT MEAN "AGO." You cannot say:
Dos semanas pasadas, which would actually mean something like
two weeks from now (a future structure), but it is not acceptable
even for that. The past participle (not the adjective)
should precede the time word-- pasado mañana - day after tomorrow.
(tomorrow having passed)
Two structures are possible:
Yo fui a México hace tres años. OR Hace tres años que fui a
México.
Last Saturday night-- La última noche del sábado. OR
El último sábado por la noche.
Then--después, entonces, luego are all three interchangeable
for sequencing events in a narration.
after-- después de + infinitive or noun
before--antes de + infinitive or noun
To use "before" and "after" followed by
complete clauses (conjugated verbs), you'll need to look at
the Subjunctive Mood
and the use of Connective Words.
This is for students well into the SECOND YEAR of Spanish.
I don't recommend using this material if you are in first year.
Questions
How long ago did you go to Mexico?
¿Cuánto tiempo hace que fuiste a México? (in oral Spanish,
the word "tiempo" is often omitted--¿Cuánto hace que
fuiste a México?) Hace tres años que fui. OR-- Fui
hace tres años.
¿Cuándo ...? is used as it is in the present--no new structures.
¿A qué hora ...? is also used as you learned before.