1. Website > Blog > Blog Posts → + Add New (/admin/blog/0).
2. Fill in Title (the URL Slug is generated as you type; the address preview …/blog/<slug> updates live), Author (defaults to you; search any staff user) and Categories.
3. Choose the Template – Blog Post Template (standard post layout with toggles Show Post Header / Show Post Main Content / Show Post Navigation / Show Post Related) or DIY to compose it from the Blog modules.
4. Optionally upload a Featured Image (JPG/PNG/WebP, 1200×630 px recommended).
5. Save. In the editor add or edit the content modules (with DIY: Blog Post Header, Text Block Simple, Blog Post Navigation, Blog Post Related).

Required: Title, Author ("Author empty"), slug ("Url empty"), unique slug ("Url Exists in other post: <title>"). Blog posts are public as soon as they are saved – there is no draft state, so keep unfinished posts out of the Blog List by not linking them, or delete them.