1. Edit > Preferences > Add-ons, menu ⌄ (top right) > Install from Disk…, then pick bizen3d-1.0.0.zip.
2. In the 3D view, press N and open the Bizen3D tab.
3. Click Install Engine (about 14 GB, once). The download can be paused and resumed; a cut installation picks up where it stopped.
4. Optional, from their own blocks: Add Pixal3D, Multi-View and Enhance Detail.
5. Drop a picture on the Image card (or Choose Image, or Paste), pick the engine, click Generate. The model is placed on the 3D cursor.
6. With the model selected: Enhance Detail, Upscale Texture, or Retopology > Remesh into Quads.

Settings (button at the top of the panel): the engine folder, when the engine frees the graphics card, and the third-party licenses.