Text-to-3D
Text-to-3D takes a text prompt to generate a preview. If you're happy with the preview, you can pay to create the final mesh model.
Generating 2D Preview
Generating a 2D Preview is fast, usually only taking a few seconds.
The 2D preview can be viewed, including the texture it will have. You can redo the 2D Preview by clicking the "Add variant" button. 
Generating final model
If you like the Preview, you can make it full 3D model by clicking
to begin the generation process.
3D Model Details
Before generating the full 3D Model, you can choose from the available AI Models.
Additionally, you can:
Generate PBR Textures - Generates PBR textures for this model.
Allow NSFW - Allows generation of NSFW content, if the model allows.
The final model can be exported or downloaded.
Downloaded - Downloaded as a DAE or GLB file. 
Exported to SL - Send to your avatar in SL, for a cost. 
You can also re-texture your model by clicking the "Add texture variant" button. 