Vicuna's fine-tune of the LLaMA weights are available for download, called "deltas". So you get the LLaMA weights (somewhere), then apply the Vicuna deltas to

Vicuna's fine-tune of the LLaMA weights are available for download, called "deltas". So you get the LLaMA weights (somewhere), then apply the Vicuna deltas to them to end up with the Vicuna model.