Hi @emilyt60792997,
Suggest you re-read the Portfolio getting started tutorials. Don't overthink this. It's really very simple.
https://help.myportfolio.com/hc/en-us/articles/360035497414-Getting-Started-Steps
1. Chose a layout theme. There are 12 themes to choose from.
https://help.myportfolio.com/hc/en-us/articles/360035995733-Themes-features
2. Click the plus sign to create a new project page.
3. Add some images and text to your page.
4. When prompted, give your project page a title and a cover image.
5. Publish your site.
6. Repeat for other project pages.
When done, your landing page will contain links to your various project pages. That's it in a nutshell.
Hope that helps. But post back if you have more questions.