Blender stoi w kuchni przy czajniku, a mikser trzymam w szafce nad stołem.

Polish often uses a position verb when saying where something is:

• stać = to stand
• leżeć = to lie
• wisieć = to hang

A blender sitting upright on a kitchen surface is naturally described as stoi.
So Blender stoi w kuchni sounds more specific and natural than Blender jest w kuchni.

Jest is possible, but it is more neutral and less visual.

Yes, trzymać can mean to hold, but it also very often means to keep or to store something somewhere.

So:

• trzymam mikser w szafce = I keep/store the mixer in the cupboard
• not necessarily I am physically holding it

This is a very common use of trzymać in Polish.

Because Polish usually drops subject pronouns when they are clear from the verb form.

The ending -am in trzymam already tells you it means I keep.

So:

• trzymam = I keep
• ja trzymam = I keep, but with extra emphasis on I

Polish does this a lot, unlike English.

A often links two parts of a sentence with a slight contrast or topic shift.

Here it feels like:

• The blender is in one place, and the mixer, on the other hand, I keep somewhere else.

So a is not a strong but like ale, but it is also not just a plain and like i.
A natural English translation may still use and, but the Polish a gives a small contrast.

Polish word order is much more flexible than English word order.

Both are possible:

• trzymam mikser w szafce... = more neutral
• mikser trzymam w szafce... = puts more focus on mikser

In this sentence, mikser is moved forward to contrast it with blender from the first half of the sentence. That makes the structure feel neat and natural.

Both are in the locative case because w here means in and describes location.

So:

• kuchnia → w kuchni
• szafka → w szafce

These forms answer the question where?

• Gdzie stoi blender? — W kuchni.
• Gdzie trzymasz mikser? — W szafce.

The preposition przy means by, next to, or near, and it takes the locative case.

So:

• czajnik → przy czajniku

That is why you get przy czajniku, not the basic form czajnik.

Here nad means above / over, and because it describes a fixed location, it takes the instrumental case.

So:

• stół → stołem
• nad stołem = above the table

This is why the ending is different from przy czajniku.

Because mikser is a masculine inanimate noun.

In Polish, many masculine inanimate nouns have the same form in:

• nominative singular
• accusative singular

So:

• nominative: mikser
• accusative: mikser

That is why trzymam mikser looks unchanged, even though mikser is the direct object.

The same is true for blender.

No. Szafka and szafa are related, but they are not the same thing.

• szafa = a wardrobe / large cabinet / closet
• szafka = a small cabinet, cupboard, or little storage unit

In a kitchen, szafka usually means cupboard or cabinet.

So w szafce nad stołem most naturally means in the cupboard/cabinet above the table.