The purpose of today's session is for students to demonstrate their knowledge of the content and their ability to use the standards of mathematical practice while solving problems. You can organize the session however you prefer. I like to have students work on the quiz first, individually and silently, to ensure that they have time to finish the quiz during class. Then once they finish they can start organizing their portfolio and producing their write-ups to explain how their work shows their use of the mathematical practice standards.
While students work on the quiz, I write some brief narrative feedback to each student that focuses on their habits of work and collaboration. Generally, I focus more on their attitude and effort in these comments, because I will give them feedback on their use of the practice standards when I review their portfolio.
Once I finish writing the comments, I am available to review students' portfolio writing. Though there isn't time to read all of these, I encourage students to ask me or their peers for feedback on the quality of their writing before submitting your portfolio.
When it comes to the portfolio, some students like to take the time to make a pretty cover or to include other decorations. As long as the content is solid and the written reflection is high quality, they can take the time to do this, as I think it shows pride in their work. If students are doing this in lieu of producing a high quality portfolio or a decent write-up, then I discourage them or ask them to take care of the quality of the content first.