Thank you for reaching out and posting this question!
I understand that you’re looking to change the way the menu is displayed on the Debut theme. While it is possible to explore this through custom coding, you may need to consider hiring a developer to assist you with this if you’re not comfortable working with coding languages (eg. HTML, CSS, JavaScript, and Liquid). If you need help finding a developer, then I’d encourage taking a look at our directory of certified developers on Shopify Experts.
Alternatively, an easier option may be using a third-party app, like Mega Menu. Mega Menu offers robust menu customizations and layouts, and they can be added to any theme. If you’d like to explore more apps, then I’d recommend taking a look at our filtered list of mega menu or menu apps. That said, if you need help with a third-party app, the app developer is always available to assist you. Simply reach out to the developer through the contact information found in the Support section of their app’s page.
We also have some new themes available now, did you get a chance to explore any of them? If not, then you can also check out our new free themes.
Do you have a marketing plan prepared for your cosmetic business? Have you considered using something like Shopify Inbox to interact with customers live on your store?