For best outputs:

Sampler: Heun.

Steps: 60, cfg 7, CLIP skip 2.

VAE: none required.

Pos prompt: use the model's trigger "Science fiction", followed by which you want to see, for example "Science fiction, cinematic SCI-FI environment, ruins of an ancient alien civilization lie beneath the sands of a desert, with intricately carved relics hinting at their advanced technology, cyber sci-fi, photorealistic, movie". This model is specially trained in creating sci-fi backgrounds, either indoors or outdoors.

Neg prompt: you can leave it empty, although for my example runs i used this one "(bad-artist:1.0), (loli:1.2), (worst quality, low quality:1.4), (bad prompt version2:0.8), lowres, bad anatomy, bad hands, (text), (watermark), error, missing fingers, extra digit, fewer digits, croppedworst quality, low quality, normal quality, ((username)), blurry, (extra limbs)."