På hyllan bredvid fönstret står en liten tavla och några böcker.

Because Swedish uses V2 word order in main clauses: the finite verb must come in the second position.

The sentence begins with På hyllan bredvid fönstret (“On the shelf next to the window”), so that first element takes position 1. Then the verb står must come next:

• På hyllan bredvid fönstret = position 1
• står = position 2

After that comes the subject:

• en liten tavla och några böcker

So the more neutral order would be:

• En liten tavla och några böcker står på hyllan bredvid fönstret.

But when the location is moved to the front, Swedish requires inversion:

• På hyllan bredvid fönstret står en liten tavla och några böcker.

English does this only sometimes for style, but in Swedish it is a normal grammar rule.

The subject is:

• en liten tavla och några böcker
  “a small painting/picture and some books”

Even though the subject comes after the verb here, it is still the subject.

A good test is to put the sentence into more neutral word order:

• En liten tavla och några böcker står på hyllan bredvid fönstret.

That makes it easier to see.

Hyllan is the definite singular form of hylla (“shelf”):

• en hylla = a shelf
• hyllan = the shelf

Swedish often uses the definite form where English might also use the. Here it means a specific shelf, not just any shelf:

• På hyllan = on the shelf

The definite article is usually attached to the end of the noun in Swedish instead of being a separate word.

For the same reason: fönstret is the definite singular form of fönster.

• ett fönster = a window
• fönstret = the window

So:

• bredvid fönstret = next to the window

It refers to a particular window.

In På hyllan bredvid fönstret, the phrase bredvid fönstret is understood as describing hyllan:

• hyllan bredvid fönstret = the shelf next to the window

So the whole opening phrase means:

• På hyllan bredvid fönstret = on the shelf next to the window

This is very natural in Swedish. It works much like English noun phrases such as:

• the chair by the door
• the table near the wall

Swedish often uses position verbs where English just says is/are.

Common ones are:

• stå = stand
• ligga = lie
• sitta = sit

So instead of saying “there is/are,” Swedish often describes the physical position of the object.

Here:

• står suggests that the items are in an upright or standing position on the shelf.

Examples:

• Boken ligger på bordet. = The book is lying on the table.
• Lampan står på bordet. = The lamp is on the table.
• Tavlan står på hyllan. = The picture/frame is standing on the shelf.

In English, “stand” may sound more marked, but in Swedish this is very normal.

Yes, a tavla often hangs on a wall, but it can also be standing, for example if it is:

• framed and leaning against the wall
• placed upright on a shelf
• propped up as decoration

So står en liten tavla suggests a small picture/frame that is standing on the shelf, not hanging.

If it were hanging on the wall, Swedish would more likely say:

• En liten tavla hänger på väggen.
  “A small painting is hanging on the wall.”

In Swedish, the present tense verb does not change for singular vs. plural.

So:

• den står = it stands
• de står = they stand

The form står stays the same.

That is why the same verb works whether the subject is:

• en tavla = a painting
• några böcker = some books
• en tavla och några böcker = a painting and some books

Because tavla is an en-word and it is singular and indefinite.

The adjective liten changes depending on gender/number/definiteness:

• en liten tavla = a small painting
• ett litet fönster = a small window
• små böcker = small books
• den lilla tavlan = the small painting

So here:

• en noun
• singular
• indefinite

therefore:

• liten

Because några already functions like some/a few.

• några böcker = some books / a few books

You do not add another article in front of it.

Compare:

• böcker = books
• några böcker = some books
• de här böckerna = these books
• böckerna = the books

It can mean either, depending on context.

• några böcker can be translated as some books
• It can also feel like a few books

Usually it simply means an indefinite small number.

Because på means on, while i means in.

A hylla is usually thought of as a surface or shelf you put things on:

• på hyllan = on the shelf

You would use i with something more like a container or enclosed space:

• i lådan = in the box
• i skåpet = in the cupboard

So på hyllan is the natural choice.

Yes, that is also possible.

That structure uses det as a kind of introductory or dummy subject, similar to English there in there is/there are:

• Det står en liten tavla och några böcker på hyllan bredvid fönstret.

This is very natural Swedish.

Your original sentence is also natural, but it gives more focus to the location by putting it first:

• På hyllan bredvid fönstret står en liten tavla och några böcker.

So the difference is mostly about focus and word order, not basic meaning.

Not always.

Tavla can mean several related things, depending on context:

• painting
• picture
• framed picture
• artwork

In this sentence, since the tavla is standing on a shelf, English might often prefer:

• a small picture
• a small framed picture
• a small painting

So painting is possible, but the exact English word depends on what kind of object you imagine.

A more straightforward version is:

• En liten tavla och några böcker står på hyllan bredvid fönstret.

That may be easier to understand at first because the order is closer to:

• subject + verb + place

But the original sentence is very common and natural Swedish because it starts with the place for emphasis:

• På hyllan bredvid fönstret står en liten tavla och några böcker.