Oh, I thought it was installed by default.
Unfortunately, it seems the GTX 770 has only 2 GB of VRAM ? The guide mentions that you would need a bare minimum of 4 GB of VRAM and even 4 GB is stretching it.
If you use the docker version (as in this guide), you can put the LoRa models in <project folder>/data/Lora (should already exist). Then you go to the webui and click on the 3rd icon at the right (below the Generate button).