Issue with identifying ndvi values using qgis

Hi William,
I put this script in and it told me there was an error to obtain images.
//VERSION=3

function setup() {

return {

input: [“B04”, “B08”],

output: { bands: 1, sampleType: “FLOAT32” }

};

}

I was following this forum to use UNIT16

I would appreciate it if you can let me know how the custom script should look like instead. Thanks!