Instance 3d Tiles in Cesium Js

Question

I am working in a forest project using angular and cesiumjs, and when I upload 100 trees into cesium ion and call it from my code, my viewer is completly slow. So, I found that instancing is a good idea to solve that problem, but I don't know how to instance it

I what tryin with this code:

const treePOsitions = [
  [-77.029383, -12.125592],
  [-77.02938,   -12.125692],
  [-77.029382, -12.125804],
  [-77.029384, -12.125916],
  [-77.029382, -12.12535]
]
const resource = await IonResource.fromAssetId(2331166);
treePOsitions.forEach((tree) =>
  this.createNAddModels({ resource, x: tree[0], y: tree[1], z: 0, modelid: 0 })
);
async createNAddModels({ resource, x, y, z, modelid }) {
    try {
      const origin = Cartesian3.fromDegrees(x, y, z);
      const hpr = new HeadingPitchRoll(0.0, 0.0, 0.0);
      const modelMatrix = Transforms.headingPitchRollToFixedFrame(origin, hpr);
      const model = varCesiumViewer.scene.primitives.add(
        await Model.fromGltfAsync({
          url: resource,
          modelMatrix: modelMatrix,
        })
      );
    } catch (error) {console.log(error)}
}

but my fps is still in 17fps and when I move fast it downs to 9fps or less. this is the correct way? or there is another way to improve the instancing and improve my fps.

Thank you!!