You can approach your topic sentences in any way that works for you, so long as you're providing an answer to the topic.
With a 'how' text, and a graphic novel like Persepolis, though, you might think about how your second approach fits with the nature of the text and topic. So say you want to talk about how the citizenry are represented as vulnerable to misuse. An interesting response could still consider that she repeatedly depicts the populous as an amorphous, indistinguishable mass. And that she does this at particular moments to emphasise the ways in which an autocratic regime gradually overturns a more liberal, progressive society.
Keep in mind that there's no predefined or predetermined answer your assessors are looking for. Instead, think of a "how" question as an opportunity to reveal how the mechanics of the text link to meaning. In Persepolis, for example, that might mean drawing a connection between Marjane's naive childhood and her gradual awakenings - telling your reader why Satrapi does this, showing you get the relationship between idea and image, is the key to these questions!
Basically, how you order your elements is up to you, so long as it's an order that makes sense. As long as you're dealing with the visual elements, and exploring these in an interesting way, you'll likely be providing a relevant answer to this type of question.