Learn Hardcore Russian: Поставь книгу на тумбочку, пожалуйста. - Please put the book on the bedside table.

Поставь is the imperative (command/request) form for ты (informal “you”) of the verb поставить (“to place/set something (upright) somewhere”).

поставить = infinitive (“to place”)
поставь = “(you) place/put (it)!”
Russian imperatives often have this short ending -ь in the ты form.

What’s the difference between поставь and положи? Aren’t both “put”?

Both can translate as “put,” but they differ in the typical orientation:

поставь (from поставить) = put something so it stands (upright), e.g. a bottle, a vase, often a book placed upright or set down as an object on a surface.
положи (from положить) = put something so it lies (flat), e.g. a book laid flat, a phone, papers.

In real life, Russians can still say поставь книгу even if the book ends up flat—it’s common and not always strictly literal, but the “standing/setting” nuance is why поставь is chosen here.

What does на тумбочку mean exactly, and why is it на + that ending?

На тумбочку means “onto the nightstand/bedside table” (or “on the small cabinet”).
На with motion (“put onto”) typically takes the accusative case, and тумбочка changes to тумбочку in the accusative singular:

nominative: тумбочка
accusative: тумбочку

So поставь … на тумбочку = “put … onto the nightstand.”

How would it change if the book is already there and I mean “it’s on the nightstand”?

Then you’d normally use на + prepositional (location, not motion):

Книга на тумбочке. = “The book is on the nightstand.”
Here тумбочка → тумбочке (prepositional singular).

A helpful shortcut:

motion/onto = на
- accusative (тумбочку)
location/on = на
- prepositional (тумбочке)

Why is книгу in that form?

Книгу is the accusative of книга (“book”) because it’s the direct object of поставь (“put (what?) the book”).

nominative: книга
accusative: книгу

Why isn’t the word for “the” used? How do I know which book?

Russian has no articles (a/the). Context supplies that information. Depending on the situation, Поставь книгу… can mean:

“Put a book…” (any book)
“Put the book…” (a specific one already known)

If you need to specify, Russian uses other tools, e.g.:

эту книгу = “this book”
ту книгу = “that book”
книгу с красной обложкой = “the book with the red cover”

What does пожалуйста do here, and where can it go in the sentence?

Пожалуйста makes it polite: “please.”
It’s flexible in position:

Поставь книгу на тумбочку, пожалуйста.
Пожалуйста, поставь книгу на тумбочку.
Поставь, пожалуйста, книгу на тумбочку. (very common in speech)

All are correct; placement changes emphasis slightly.

Is this sentence formal or informal? How do I say it formally?

Поставь is the ты (informal) imperative, used with friends, family, children, etc.

Formal/polite (вы) versions:

Поставьте книгу на тумбочку, пожалуйста. (standard polite request/command) You can also soften it further with phrasing like:
Пожалуйста, поставьте книгу на тумбочку.

What aspect is поставить, and why does it matter?

Поставить / поставить is perfective: it focuses on a completed result (“put it there (and it ends up there)”).
Its imperfective partner is ставить:

Поставь книгу… = “Put the book (once, to completion).”
Ставь книгу… can sound like “Put/place the book (in general / as a process),” and is less typical for a single quick request unless the context is repeated actions or instruction.

For a one-time request, perfective imperatives like поставь are very common.

How do I negate it: “Don’t put the book on the nightstand”?

Use не with the imperative:

Не ставь книгу на тумбочку. (more natural with imperfective for “don’t do that” in general) You can also say:
Не поставь… exists but is usually more specialized/rare and often sounds like “don’t end up doing it” (less neutral).
So the default “don’t do it” is Не ставь… (informal) / Не ставьте… (formal).

Could I replace на тумбочку with на тумбочке here?

Not if you mean motion (“put onto”).

Поставь книгу на тумбочку = correct for motion (accusative).
Поставь книгу на тумбочке is generally incorrect in standard usage, because на тумбочке describes location (“on the nightstand”), not destination.

What is тумбочка exactly? Does it only mean “nightstand”?

Тумбочка is a small cabinet/stand, often:

a nightstand/bedside table (common)
a small side cabinet next to a sofa, in a hallway, etc.

If you specifically want “bedside table,” you can also say прикроватная тумбочка (“bedside nightstand”).

What word order is typical here? Could it be Пожалуйста, книгу поставь на тумбочку?

The neutral order is what you have: Verb + object + destination:

Поставь книгу на тумбочку, пожалуйста.

Other orders are possible, but they shift emphasis:

Книгу поставь на тумбочку… = emphasizes the book (not something else).
На тумбочку поставь книгу… = emphasizes the destination (not somewhere else).

Russian word order is flexible, but learners should start with the neutral pattern.

How do I say “Put the book on the nightstand” vs “Put the book into the nightstand (e.g., inside a drawer)”?

“onto/on” = на тумбочку
“into/inside” = в тумбочку (accusative with в for motion)
If you mean specifically into a drawer/cabinet, you might say:
Положи книгу в ящик тумбочки. = “Put the book into the nightstand drawer.”