La notizia che ho letto sul giornale stamattina è molto importante.

In Italian, singular countable nouns usually need an article. Notizia means news item or piece of news, so la notizia is the news / the piece of news.

Also, Italian notizia is singular. It is not like English news, which looks plural but is grammatically singular.

Here che is a relative pronoun meaning that, which, or the one that depending on how you translate it.

In La notizia che ho letto..., che connects la notizia to the extra information ho letto sul giornale stamattina.

So the structure is:

• la notizia = the news item
• che ho letto = that I read

Italian often uses che where English would use that or sometimes leave it out entirely.

Ho letto is the passato prossimo, a very common past tense in Italian. It means I read in the sense of I have read / I read earlier.

It is formed with:

• ho = I have
• letto = read

A native English speaker should notice that Italian uses this tense very often for completed past actions, especially in everyday speech.

• leggo = I read / I am reading now
• ho letto = I read / I have read
• lessi = I read, but this is the remote past and is not the normal everyday choice in most spoken Italian

Because with avere as the auxiliary verb, the past participle usually does not agree with the direct object in normal usage.

So you get:

• ho letto la notizia not
• ho letta la notizia in standard everyday use

The default form is letto.

You may sometimes learn that agreement can happen with certain object pronouns, but in this sentence the normal form is simply ho letto.

Sul is a contraction of su + il.

So:

• su = on, in
• il giornale = the newspaper
• sul giornale = in the newspaper / in the paper

Italian commonly combines prepositions with articles:

• su + il = sul
• a + il = al
• di + il = del
• in + il does not contract in the same way, so be careful there

Stamattina means this morning, and here it tells you when I read it.

Italian adverbs and time expressions are fairly flexible in position, but this placement sounds natural:

• che ho letto sul giornale stamattina

It groups the extra information in a smooth, natural order:

• what you did: ho letto
• where: sul giornale
• when: stamattina

You could also hear:

• La notizia che stamattina ho letto sul giornale... but the original sentence is more neutral and common.

Grammatically and naturally, it refers to when the reading happened: the news that I read in the newspaper this morning.

So stamattina is linked to ho letto, not to notizia itself.

If you wanted to make a different idea clearer, Italian would usually rephrase the sentence.

This is the main clause of the sentence.

The sentence has two parts:

1. La notizia che ho letto sul giornale stamattina
   = the subject, with extra description attached

2. è molto importante
   = the main statement about that subject

So:

• è = is
• molto importante = very important

The whole sentence says that this particular news item is very important.

Because molto here is an adverb, not an adjective.

• molto importante = very important

When molto means very, it does not agree with the noun. It stays molto.

Compare:

• una notizia molto importante = a very important piece of news
• molta notizia would not work here in the same way

Agreement happens with adjectives, but here molto is modifying importante, not notizia.

Because importante is an adjective with the same form for masculine and feminine singular.

So:

• un libro importante
• una notizia importante

The plural changes:

• libri importanti
• notizie importanti

In this sentence, notizia is singular, so importante stays singular too.

It is built like this:

• La notizia = subject
• che ho letto sul giornale stamattina = relative clause describing the subject
• è molto importante = main clause

A simple way to see it:

[The news] [that I read in the newspaper this morning] [is very important].

This is a very common Italian pattern:

• noun
• che
  • extra information
• main statement

Yes. That is also correct.

Both are natural:

• che ho letto sul giornale stamattina
• che ho letto stamattina sul giornale

The difference is mostly rhythm and emphasis, not basic meaning.

The original sentence sounds very normal and balanced, but Italian often allows this kind of movement with time and place expressions.

Usually giornale means newspaper, either physical or sometimes online depending on context.

In this sentence, sul giornale most naturally means in the newspaper / in the paper.

Italian often uses su where English uses in for newspapers, magazines, websites, and similar sources:

• sul giornale
• sul sito
• sulla rivista

So even if English says in the newspaper, Italian says on the newspaper literally, but you should translate it naturally, not word for word.