Я положил корм в миску для кошки.

Положил is the past tense of положить, which means to put / to place. In this sentence it describes a completed action: the speaker put the cat food into the bowl.

This verb is perfective, so it focuses on the result or completion of the action.

A useful pair to know is:

• класть = imperfective, to be putting / to put habitually
• положить = perfective, to put (successfully, as a completed act)

So:

• Я положил корм... = I put the food... / I have put the food...
• Я клал корм... = I was putting the food... or I used to put the food...

Yes. In Russian past tense, the verb agrees with the subject in gender and number.

• положил = masculine singular
• положила = feminine singular
• положило = neuter singular
• положили = plural

So Я положил tells you the speaker is male, or at least grammatically presented as masculine.

If a woman said it, it would be:

• Я положила корм в миску для кошки.

Корм is the direct object of the verb положил, so it is in the accusative case.

However, корм is a masculine inanimate noun, and for many masculine inanimate nouns, the accusative singular looks the same as the nominative singular.

So:

• nominative: корм
• accusative: корм

That is why the form does not change.

Because Russian uses different cases after в depending on the meaning:

• в + accusative = motion into something
• в + prepositional = location in something

Here the food is being moved into the bowl, so Russian uses в миску.

Compare:

• Я положил корм в миску. = I put the food into the bowl.
• Корм лежит в миске. = The food is in the bowl.

So this is a very common pattern:
direction/change of location → accusative
static location → prepositional

Миску is the accusative singular of миска.

The noun миска is feminine and ends in -а. For many feminine nouns of this type:

• nominative singular: -а
• accusative singular: -у

So:

• миска → миску

This is a very common declension pattern:

• книга → книгу
• машина → машину
• кошка → кошку

Because the preposition для always takes the genitive case.

So:

• кошка = nominative
• кошки = genitive singular

That is why the sentence says для кошки.

This phrase means for the cat in the sense of intended for the cat or belonging to the cat's use, not necessarily to the cat as an indirect object.

So:

• миска для кошки = a bowl for the cat

It can feel like either in English, depending on context.

Literally, миска для кошки means a bowl for the cat. In natural English, that may also be understood as the cat’s bowl.

Russian often uses для + genitive to describe the purpose or intended user of something:

• еда для детей = food for children
• клетка для птицы = a cage for a bird
• миска для кошки = a bowl for a cat / the cat’s bowl

So the phrase is about purpose rather than possession in a strict grammatical sense.

Usually корм means feed or pet food / animal food, not ordinary human food.

So in this sentence, корм is exactly the natural word for cat food.

Compare:

• корм = animal feed, pet food
• еда = food in general
• пища = food/nourishment, more formal

For a cat, корм is the expected choice.

No, Russian word order is fairly flexible. The sentence

• Я положил корм в миску для кошки.

is a neutral, natural order.

But you can move parts around to change emphasis:

• Корм я положил в миску для кошки.
  Emphasizes the food.

• В миску для кошки я положил корм.
  Emphasizes into the cat’s bowl.

Even though the order can change, the cases help show what each word is doing grammatically.

Russian does not have articles like a/an and the.

So миску can mean:

• a bowl
• the bowl

and корм can mean:

• food
• the food
• some food

The exact meaning comes from context.

That is normal in Russian, and learners have to get used to understanding definiteness from the situation rather than from articles.

The standard stress is:

• Я положи́л ко́рм в ми́ску для ко́шки.

Word by word:

• Я = ya
• положи́л = pala-ZHEEL roughly
• ко́рм = korm
• в = v
• ми́ску = MEES-koo
• для = roughly dlya
• ко́шки = KOSH-kee

A few important points:

• The stress in положи́л is on the last syllable.
• миску is stressed on the first syllable: ми́ску.
• кошки is stressed on ко́-.

Unstressed vowels are often reduced in real pronunciation, so spoken Russian may sound less like the spelling than you expect at first.