Learn Hardcore Turkish: Konser başlamadan mataradan su içtik; koro ve şarkıcı sahneden birlikte indi. - Before the concert started we drank water from the canteen; the choir and the singer left the stage together.

It’s başla- (start) + -ma- (neg.) + -dan/-den (ablative) → the converb -madan/-meden.
In time expressions, -madan commonly means “before (doing)”: Konser başlamadan (önce) = “Before the concert started.”
When the subject of both actions is the same, -madan can mean “without doing”: Konuşmadan ayrıldı “He left without speaking.” In our sentence the subjects differ, so the meaning is “before.”

Do I need to add önce after başlamadan?

No. Konser başlamadan is idiomatic on its own. Adding önce (Konser başlamadan önce) is a bit more explicit and slightly more formal, but both are fine.

Why is there no biz? How do we know it’s “we drank”?

Turkish usually drops subject pronouns. The verb ending shows the subject:

iç-ti-k = drank-PST-1PL → “we drank.”
You’d use Biz içtik only for emphasis (e.g., “We drank (not them)”).

Why isn’t it suyu içtik? When do I add the accusative?

In Turkish, a definite direct object takes accusative, an indefinite one stays bare:

su içtik = “we drank (some) water” (indefinite, no accusative).
suyu içtik = “we drank the water” (specific/previously mentioned water).

Why do we use -dan/-den in mataradan and sahneden?

That’s the ablative case “from.”

mataradan su içtik = we drank water from the canteen/flask. With containers/sources, içmek uses ablative.
sahneden indi(ler) = (they) came down from the stage. The verb inmek (“to get off/come down”) takes the source in ablative.
Be careful: sahneye indi means “(he/she) stepped onto the stage” (directional -e = “to”).

Shouldn’t it be indiler (plural)? Why is it indi?

With an explicit 3rd‑person plural subject, the plural ending on the verb is optional:

Koro ve şarkıcı sahneden birlikte indi / indiler = both correct. Many speakers prefer indiler when the subject is human to stress plurality/agency, but indi is very common in neutral narration.

Can I drop or replace birlikte? What about beraber or ile birlikte?

birlikte = “together” (adverb). You can drop it; the sentence still means both came down, but birlikte makes the “together” idea explicit.
Alternatives: beraber (synonym), or … şarkıcıyla birlikte … / … koro ile şarkıcı … (“together with”).

How flexible is the word order? Could I say Su içtik mataradan?

Turkish word order is flexible, but the neutral pattern is [time] [source] [object] [verb]:

Neutral: Konser başlamadan mataradan su içtik.
Variants for focus/emphasis are possible: Su içtik mataradan (emphasizes “water”), Mataradan su içtik (neutral), Mataradan içtik su (marked, usually poetic/spoken for emphasis).

Why a semicolon here? Could I use a period or ve instead?

The semicolon links two closely related independent clauses. A period would also be fine:

… içtik. Koro ve şarkıcı …
Using ve to join the whole clauses is possible but heavier; the semicolon keeps them distinct while showing the sequence/connection.

Other ways to say “before the concert started”?

Konser başlamadan önce … (most common explicit form)
Konserin başlamasından önce … (nominalized: konser-in başla-ma-sı-ndan önce) Avoid: başladıktan önce (incorrect; use başlamadan önce for “before,” and başladıktan sonra for “after”).

Why is it spelled içtik and not içdik?

Past tense is -DI, but:

Vowel harmony picks i (last vowel in iç- is front), so → -di.
After a voiceless consonant (ç), d devoices to t → -ti.
1st‑person plural adds -k → iç-ti-k = içtik.

How do I pronounce the special letters ş, ç, ı?

ş = “sh” as in “shop”: şarkıcı, başlamadan.
ç = “ch” as in “church”: içtik.
ı (dotless) = close, unrounded vowel; approximate “uh” (but central): şarkıcı ≈ “shar-kuh-juh”.

What exactly is a matara?

A canteen/flask/water bottle (reusable container you drink from); in many contexts su matarası = “water bottle.”