Learn Hardcore Hungarian: Én várlak titeket a téren. - I am waiting for you plural in the square.

Neutral, most common: Várlak (titeket) a téren.
With emphasis/contrast on the subject: Én várlak (titeket) a téren. (meaning: It’s me, not someone else, who’s waiting)

What does the ending -lak in várlak mean?

-lak/-lek is a special verb ending used when:

the subject is first person singular (“I”), and
the direct object is second person (“you,” singular or plural, informal). It bundles both into the verb: várlak = “I am waiting for you.”
Choice of -lak vs -lek follows vowel harmony:
back-vowel stems: várlak, látlak, hívlak
front-vowel stems: szeretlek, értelek

If várlak already says “I’m waiting for you,” why add titeket?

Because -lak/-lek doesn’t show number. Várlak can mean “I’m waiting for you” (one person) or “you all.”
Adding titeket disambiguates and/or emphasizes that it’s plural “you”:

Várlak titeket a téren. = “I’m waiting for you guys at the square.”
You can omit titeket if context makes plural clear.

Where does titeket normally go in the sentence?

Placement depends on emphasis (focus). The focused element sits right before the verb. Examples:

Emphasis on location (most neutral here): A téren várlak (titeket).
Emphasis on who is being waited for: Titeket várlak a téren.
Emphasis on the subject: Én várlak titeket a téren. All are grammatical; they just highlight different things.

Can I say várok téged instead of várlak?

Sounds off to many speakers. The natural options are:

Use the special ending: Várlak (titeket).
Or use the postpositional construction: Várok rád/rátok.
Avoid mixing: don’t say várlak rád or várlak rátok (that’s ungrammatical).

What’s the difference between várlak (titeket) and várok rád/rátok?

Both mean “I’m waiting for you (sg/pl).”

Várlak (titeket) uses a direct object; slightly more compact.
Várok rád/rátok uses the postposition -ra/-re (“onto”), very idiomatic with “wait.”
You generally choose one pattern or the other; you don’t combine them.

What case is téren, and why is it used here?

Téren is the superessive case (-n), often used for “on/at” open surfaces/areas:

téren (on/at the square), utcán (in the street), hídon (on the bridge).
So a téren ≈ “at/on the square.”

Why is there an article: a téren? Could I drop it?

Hungarian usually keeps the definite article even with case endings:

a téren = “on the square.”
Dropping it often sounds headline-like or generic. With named squares you also typically keep it:
a Deák téren, a Szabadság téren (both common in speech and writing).

Does a téren mean “at,” “on,” or “in” the square?

All three are plausible translations depending on English style. Literally it’s “on,” but the best natural English is often “at the square.” Context decides:

Meeting point: “at the square.”
Emphasizing surface: sometimes “on the square.”
Urban space: often still “at.”

How do I say “to the square” and “from the square”?

Use the directional pairs:

to/onto: a térre (illative/allative: -ra/-re)
from/off: a térről (delative: -ról/-ről)
Examples:
Odamegyek a térre. (I’m going to the square.)
Eljövök a térről. (I’m coming from the square.)

How would I express the future: “I’ll wait for you (guys) at the square”?

Hungarian often uses the present for near-future plans:

Várlak (titeket) a téren. (context supplies futurity)
To make it overtly future:
Majd várlak titeket a téren.
Ott foglak várni titeket.
With a completive nuance: Megvárlak titeket a téren.

What’s the nuance of megvárlak vs plain várlak?

Megvár adds a completive/resultative idea: “wait up for,” “wait until you arrive/finish.”

Várlak = I’m waiting for you (general).
Megvárlak = I’ll specifically wait until you get there / I won’t leave before you arrive.

How do I say this politely/formally to one person or a group?

The -lak/-lek ending is only for informal “you.” With formal Ön/Önök, use the definite conjugation:

To one person (formal): Várom Önt a téren.
To a group (formal): Várom Önöket a téren.
Don’t say várlak Ön(öke)t.

How do I negate it or turn it into a question?

Negation: Nem várlak (titeket) a téren.
Yes/no question: Várlak (titeket) a téren?
Wh-question: Hol várlak (titeket)? — A téren várlak (titeket).
With the question particle: Ott várlak-e (titeket)?

How would I say it to just one friend?

Simply drop the plural object pronoun:

Várlak a téren. (singular “you”)
If you want to be crystal clear it’s singular, you can add téged for emphasis:
Téged várlak a téren. (focus on “you (singular) in particular”)

Any quick notes on pronunciation and stress?

Primary stress is always on the first syllable of each word: Én VÁR-lak TI-te-ket a TÉ-ren.
Long vowels: á in vár-, é in téren are long.
Final -n in téren is a clear [n].