Learn Hardcore Turkish: Yarın sabah ofiste toplantı yapmak istiyoruz. - We want to hold a meeting at the office tomorrow morning.

Vowel harmony picks -da/-ta after back vowels (a, ı, o, u) and -de/-te after front vowels (e, i, ö, ü).
After a voiceless consonant (f, s, t, k, ç, ş, h, p), d becomes t. Since ofis ends in voiceless s and has a front vowel, you get -te → ofiste.

Do I need to say biz?

No. The ending -uz in istiyoruz already marks first person plural (we). You add Biz only for emphasis or contrast, e.g., Biz yarın sabah ofiste toplantı yapmak istiyoruz (as opposed to others).

Why use toplantı yapmak instead of just a noun or another verb?

Turkish often uses a light verb with a noun. Toplantı yapmak literally means to do/hold a meeting and is the idiomatic way to say have a meeting.

Toplanmak = to gather/assemble (the group comes together).
Görüşmek = to meet/discuss with someone.
Buluşmak = to meet up (often more informal). Here, toplantı yapmak best matches hold a meeting.

Can I say toplantı istiyoruz?

It’s grammatical but different in meaning. Toplantı istiyoruz = We want a meeting (to be arranged/provided). Toplantı yapmak istiyoruz = We want to hold/have a meeting (we intend to do it). In your sentence about your own plan, the light-verb form is the natural choice.

Why isn’t there bir before toplantı?

Indefinite singular count nouns often appear without bir when the number isn’t the point, especially in light-verb collocations (e.g., alışveriş yapmak, kahvaltı yapmak). You can add bir (bir toplantı yapmak) to stress one meeting or to be a bit more specific, but it’s not required.

Why doesn’t toplantı take the accusative (-ı)?

Indefinite direct objects in Turkish remain unmarked. Toplantı yapmak is indefinite, so no accusative. If you mean a specific meeting already known in context, mark it: Toplantıyı yapmak istiyoruz = We want to hold the meeting.

Why yapmak istiyoruz and not yapmayı istiyoruz?

Both are grammatical. The bare infinitive (-mek/-mak) is by far the most common and neutral with istemek when the subject is the same: toplantı yapmak istiyoruz. The accusative verbal noun (-meyi/-mayı) can sound more formal or put extra emphasis on the action as a thing: toplantı yapmayı istiyoruz. In everyday speech, prefer -mek/-mak.

What’s the default word order here, and can I move things around?

Neutral Turkish order is typically Time–Place–Object–Verb, which your sentence follows: Yarın sabah (time) ofiste (place) toplantı yapmak (object/action) istiyoruz (verb). You can front different elements for emphasis, but keep the finite verb at the end. To highlight the place more clearly, a common rewrite is: Toplantıyı ofiste yapmak istiyoruz (focusing the location by bringing it close to the verb complex).

What tense is istiyoruz, and how would isteriz or isteyeceğiz change the meaning?

İstiyoruz uses the progressive -iyor and expresses a current intention/desire: we want (now).
İsteriz (aorist) is more general/habitual or can sound like would like in a polite or tentative context.
İsteyeceğiz is future: we will want. If the plan is fixed rather than just desired, you might say Yarın sabah ofiste toplantı yapacağız (We will have a meeting…).

How would I turn this into a polite suggestion?

Use the hortative or a suggestion structure:

Yarın sabah ofiste toplantı yapalım mı? (Shall we have a meeting…?)
Yarın sabah ofiste toplantı yapsak mı? (What if we had a meeting…?)

Is yarın sabah the only correct order? Can I say sabah yarın?

Use yarın sabah. That’s the natural fixed order for tomorrow morning. Variants include yarın sabahleyin or more specific phrases like yarın sabah erken (early tomorrow morning).

Does ofiste mean in or at?

It covers both English prepositions. Ofiste can be translated as either at the office or in the office depending on context. If you need to emphasize inside, say ofisin içinde.

Can you break the sentence down?

Yarın = tomorrow
sabah = morning
ofis-te = office-LOC (in/at the office)
toplantı = meeting
yap-mak = to do/hold (infinitive)
ist-iyor-uz = want-PROG-1PL (we want)

How would I say at our office or in the meeting room?

Ofisimizde = at/in our office.
Toplantı odasında = in the meeting room. Example: Yarın sabah ofisimizde toplantı yapmak istiyoruz. or Yarın sabah toplantı odasında toplantı yapmak istiyoruz.