There are three ways to start a piece of content, and all three open in the same editor. Click New at the top of the app sidebar to see them:
SERP research studies what already ranks for your keyword before you write. You create the content from the finished research.
New content starts new content straight away, with the type picker.
Import & optimize brings in content you already have, from a URL, Markdown or a paste.
Start from scratch
Choose New → New content. The dialog asks What are you making?

Pick a type: Long-form content, News article or Commercial page. The types listed under On the roadmap are not available yet.
Give it a title, or leave it as Untitled and name it later in the editor.
Pick a project to file it under.
Click Create content.
Commercial pages
Choosing Commercial page asks two more things:
The page type: Product page, Service page or Landing page.
What kind? SaaS or E-commerce for a product page, B2B or Local for a service page, Solution or Comparison for a landing page. Your pick decides which sections the page starts with.
A commercial page is written from your business context. When your context is ready, the dialog picks the offering the page sells. When several qualify, you can pick up to three, and with two or more choose whether one leads or they get equal weight. If you have no business context yet, the dialog asks for the URL of a page of your website about your business, such as your About page, and reads it while the draft opens. You can skip that: the editor then asks for your context in a short setup dialog. See When a commercial page asks for your business context.
Start from research
When a research is ready, click Create content on it. From long-form research you can choose Long-form or News article. Commercial research creates the page type it researched. Either way, the research stays attached to your content so its findings are at hand while you write.
For an article, choose how to start:
Empty with outline opens a draft with the outline from your research, ready for you to write.
Generate with AI has the agent draft the full article from the research while you watch. You can add Instructions for the agent and choose its models before it starts.
For a commercial page, Empty with page plan opens a draft seeded with your page plan, and Generate with AI has the agent write every section from your business context. Research for commercial pages covers that path in detail.
You can create as much content as you like from one research.
Attach research later
Started from scratch and want research after all? Open More Options → Attached research in the editor and pick a research. The same menu lets you detach it. See The editor, the complete guide.