Does the word "mark" in this context refer to a starting line of the racing track?

What does "set out" mean?

"Set out" is actually a phrasal verb. Here it is being used in an intransitive way to mean to start doing or working on something in order to achieve an aim. In this case the aim is to become an "attorney". Ex: When we set out on this project, we knew it would be difficult. Ex: They set out to build their own house.

Can I say "butter of peanut" instead of "peanut butter"?

Unfortunately, you cannot use "butter of peanut." The correct term is "peanut butter." "Peanut" functions as an adjective here to indicate the type of butter. Other types of butter will have "butter" placed at the end as well. Ex: Recently, I've been using almond butter instead of peanut butter in my sandwiches. Ex: Peanut butter cookies are super easy and delicious to make.

What does "sister division" mean?

"Sister division" here means a division (department; company) that is related or owned by the same entity. Here, it is referring to "Industrial Light & Magic," which is another VFX and animation studio that they frequently collaborate on works with. "Sister" is often used as an adjective to mean to have a close relationship with X due to shared interests. For example, you may have heard of the term "sister city" before. Ex: The manager of our sister company is here for a meeting today. Ex: Taipei has been the sister city of Seoul since 1968.

What does the word "perplexed" mean? Could you please tell me some examples?

"Perplexed" means to be puzzled, uncertain, or confused. Ex: I am perplexed by his speech. I didn't understand what his point was. Ex: This puzzle is perplexing. Ex: Many are perplexed by the coronavirus.

Does the word "mark" in this context refer to a starting line of the racing track?

Yes, that's right! "Mark" is the place where the runners start the race. Either a line or starting blocks! Ex: I was on my mark, but I froze when they yelled, "go." Ex: The starting mark is over here.