What does LOD_Index have to do with USkinnedMeshComponent::ComputeSkinnedPositions

So this is my code:

TArray< FVector > OutPositions;
	TArray< FMatrix > CachedRefToLocals;
	const FSkeletalMeshLODRenderData &LOD = mesh->GetSkeletalMeshRenderData()->LODRenderData[LOD_Index];
	const FSkinWeightVertexBuffer SkinWeightBuffer = LOD.SkinWeightVertexBuffer;
	mesh->GetCurrentRefToLocalMatrices(CachedRefToLocals, LOD_Index);
	USkeletalMeshComponent::ComputeSkinnedPositions(mesh, OutPositions, CachedRefToLocals, LOD, SkinWeightBufffer);

I don’t know what to do with it. I just want to get all of my mesh vertices