אני רוצה לספר לכם על הסרט שראיתי.

A natural word-by-word breakdown is:

• אני = I
• רוצה = want
• לספר = to tell
• לכם = to you
• על = about
• הסרט = the film / the movie
• שראיתי = that I saw

So the structure is very close to English: I want to tell you about the film that I saw.

Yes, Hebrew often drops subject pronouns, but it depends on the tense.

In this sentence, רוצה is a present-tense form. In the present tense, Hebrew verbs usually do not show person clearly, so רוצה by itself could mean something like want or wants, depending on context. Because of that, אני is usually included to make it clear that the subject is I.

Later in the sentence, ראיתי already includes I in the verb ending ־תי, so a separate אני is not necessary there.

In unpointed Hebrew, רוצה can be either:

• רוֹצֶה = masculine singular, pronounced roughly rotse
• רוֹצָה = feminine singular, pronounced roughly rotsa

So from spelling alone, you often cannot tell whether the speaker is male or female. You need:

• pronunciation, if you hear it spoken
• vowel marks, if they are written
• context, if neither is available

This is very common in everyday Hebrew spelling.

Because רוצה is followed by an infinitive, just like English want to tell.

• רוצה = want
• לספר = to tell

In Hebrew, infinitives usually begin with ל־, so after verbs like רוצה, יכול, צריך, you often get this pattern:

• אני רוצה ללמוד = I want to study
• אני יכול לבוא = I can come
• אני צריך ללכת = I need to go

So רוצה לספר is the normal way to say want to tell.

לכם means to you.

It is made from the preposition ל־ meaning to / for, plus a pronoun ending. Here it refers to you plural masculine or you plural mixed-gender.

אתם means you as a subject, as in you are speaking or you want. But here the meaning is tell to you, so Hebrew uses לכם, not אתם.

Compare:

• אתם רוצים = you want
• אני רוצה לספר לכם = I want to tell you

It changes depending on who you refers to:

• לך = to you singular masculine
• לך = to you singular feminine
  These are spelled the same without vowel marks, but pronounced differently.
• לכם = to you plural masculine or mixed group
• לכן = to you plural feminine

So you could say:

• אני רוצה לספר לך על הסרט שראיתי. = to one person
• אני רוצה לספר לכן על הסרט שראיתי. = to a group of women

Because the verb phrase here is לספר על = to tell about.

So:

• לספר לכם על... = to tell you about...

This is just the normal preposition Hebrew uses with this meaning.

Examples:

• לספר על המשפחה = to tell about the family
• לספר על הטיול = to tell about the trip

Because הסרט is not a direct object here.

In this sentence, הסרט comes after the preposition על, so it is part of the phrase about the film. The word את is only used before a definite direct object, not after a preposition.

Compare:

• ראיתי את הסרט = I saw the film
  Here הסרט is a direct object, so את appears.
• דיברתי על הסרט = I talked about the film
  Here הסרט comes after על, so no את

That is exactly what happens in your sentence.

ש־ is a relative marker meaning that, which, or who, depending on context.

So:

• הסרט שראיתי = the film that I saw

It connects הסרט with the clause ראיתי.

A very literal breakdown is:

• הסרט = the film
• ש־ = that
• ראיתי = I saw

In modern Hebrew, ש־ is extremely common in everyday speech and writing.

Because in modern Hebrew, ש־ is normally written as a prefix attached to the next word.

So you write:

• שראיתי
• שאמרתי
• שאני

not as separate words.

This attached form is standard and very common.

Because the ending ־תי marks first person singular in the past tense.

So:

• ראיתי = I saw
• ראית = you saw depending on gender
• ראה = he saw
• ראתה = she saw

That means Hebrew does not need a separate subject pronoun here. You could say אני ראיתי for emphasis or contrast, but the neutral form is simply ראיתי.

This word order is completely natural and neutral:

אני רוצה לספר לכם על הסרט שראיתי.

Hebrew often uses this straightforward order:

• subject
• main verb
• infinitive
• indirect object
• prepositional phrase
• relative clause

You could rearrange parts for emphasis, for example:

על הסרט שראיתי אני רוצה לספר לכם.

But that sounds more marked, as if you are emphasizing about the film I saw. The original sentence is the most ordinary way to say it.