saki ni shukudai o shite kara, geemu o shimasu.

It is read さきに.

In this sentence, 先に means first, before that, or ahead of time. It tells you that the homework happens before the game.

So:

• 先に宿題をしてから、ゲームをします。
• First, I’ll do my homework, and then I’ll play games.

Here, に helps turn 先 into an adverb-like expression.

• 先 = ahead, before, earlier
• 先に = first / beforehand / in advance

So 先に functions like first in English.

This is a very common pattern:

• 先に行きます = I’ll go first.
• 先に食べてください = Please eat first.

Because the sentence is connecting two actions:

1. do homework
2. play games

To connect them with after doing X, Japanese uses:

• verb in て-form + から

The verb here is する. Its て-form is して.

So:

• 宿題をする = to do homework
• 宿題をしてから = after doing homework

That is why して appears instead of する.

てから means after doing ....

So:

• 宿題をしてから = after doing homework

The full pattern is:

• Aてから、B
• After doing A, do B

In this sentence:

• 宿題をしてから、ゲームをします
• After doing homework, I will play games.

It strongly shows the order:

1. homework first
2. game second

It is the same word in form, but here it is part of the grammar pattern てから.

So in this sentence, から does not mean:

• because
• from

Instead, してから together means:

• after doing

This is an important beginner point: Japanese often uses the same word in different grammar patterns.

を marks the direct object of the verb.

Here:

• 宿題 = homework
• する = do
• 宿題をする = do homework

So 宿題 is the thing being done, and を marks it.

This is very standard Japanese:

• 勉強をする = do studying / study
• 仕事をする = do work
• 宿題をする = do homework

In casual speech, people sometimes drop を with する expressions, but the full standard form is 宿題をする.

Yes, します literally means do, but in Japanese many actions are expressed as:

• noun + する

So:

• ゲームをする literally = do a game
• natural meaning = play a game / play games

This is a very common Japanese way of expressing activities.

Examples:

• スポーツをする = play sports / do sports
• 勉強をする = study
• ゲームをする = play games

So even though English uses play, Japanese often uses する.

Because ゲーム is a loanword, originally from English game.

Katakana is commonly used for:

• foreign loanwords
• some onomatopoeia
• emphasis
• technical terms

So:

• ゲーム = game
• pronounced roughly gee-mu

In this sentence, it usually means video games or games in general, depending on context.

Yes, most likely I, but Japanese often leaves the subject unstated when it is clear from context.

So this sentence could mean:

• I will do my homework first, and then play games.

But depending on context, it could also refer to someone else:

• he
• she
• we

Japanese frequently omits subjects that English normally has to say.

します is non-past polite form.

In Japanese, the non-past can mean:

• present/habitual: do
• future: will do

So ゲームをします could mean:

• I play games (habitually)
• I will play games (future)

In this sentence, because of the sequence after doing homework, it is most naturally understood as a future action:

• I’ll do my homework first, and then I’ll play games.

Yes, まず could also work, but the nuance is a little different.

• 先に = first, before the other thing, beforehand
• まず = first of all / to begin with

In this sentence, 先に feels very natural because there is a clear contrast:

1. homework
2. game

It emphasizes that the homework comes before the game.

Compare:

• 先に宿題をしてから、ゲームをします。

  • I’ll do my homework first, then play games.

• まず宿題をしてから、ゲームをします。

  • First of all, I’ll do my homework, then play games.

Both are possible, but 先に strongly highlights the order relative to the next action.

Yes.

You could say:

• 宿題をしてから、ゲームをします。

This still means:

• After doing my homework, I’ll play games.

So 先に is not absolutely necessary.

Adding 先に gives extra emphasis to the idea of first or before anything else.

No, it is not strictly necessary.

You can write:

• 先に宿題をしてから、ゲームをします。
• 先に宿題をしてからゲームをします。

Both are fine.

The comma just makes the sentence a little easier to read by separating the two parts.

Japanese punctuation is often more flexible than English punctuation.

A casual version would be:

• 先に宿題をしてから、ゲームをする。

Even more casual, people may shorten it further:

• 先に宿題してから、ゲームする。

Changes:

• します → する for casual/plain style
• sometimes を is dropped in casual speech:
  • 宿題して
  • ゲームする

The polite original sentence is better for standard textbook Japanese:

• 先に宿題をしてから、ゲームをします。