The way i use it is this:
$w('#dataset1').setFieldValue('username', $w('#username').value);
dataset screen shot
For my example:
dataset1 is your datasets id as it appears on your properties panel or on the upper left side of the dataset element you call on your editor. In your case your dataset name is wrong check your dataset name.
User input is where i get the info of the user. In your case it’s going to be your items name $w(“#nomDeDeuvre”).value
On my example #username is a part of my form which is hidden somewhere on the screen cause whoever fills out this form doesn’t have to see it.
And finally fieldkey is the field that you are going to add that information in your database as it is “username” in my example.
Field Key screen shot
#userinput screenshot
and finally i put these under an event which in my case it is changing a clickbox.
You may also pick an event for yourself to trigger this operation like submitbutton onclick event maybe.
Just make sure you do it on your properties panel and double check for the event names.