Save information in gallery to Sharepoint list with Power Apps

Hello,

Goal of App

I am trying to create a power app for my business to help my accountmanagers. The goal of the app is to fill in orders when they are at a customer and then sent the purchase order of the customer.

Power app description - See attached images

I have created a power app with a vertical gallery that includes all the items I need to have them fill out namely:

Verkoper (accountmanager) - dropdownmenu - I made a list in sharepoint "verkopers" with the different sales accountmanagers and connected it to this dropdownmenu.
Datum Bestelling (order date) - date
Klant (customer) - combobox - I made a customer list in sharepoint with all the clients and their corresponding clients details and connected it to this combo box.
Aantal (amount) - text
Stier (product) - combobox - I made a product list in sharepoint with all the products and their corresponding product details and connected it to this combobox.
sexed (type) - checkbox
prijs (price) - text
korting (discount) - text
kortingspercentage (discount %) - text

When they press, add row, they can enter multiple orders at the same time if they would have to. The clear button deletes all the rows so they could process a new order of a different customer. I also included a save button so when they press this, the information in the different fields is transferred to a list named "bestellingen" (orders) in sharepoint. Unfortunately I cannot get the save button to work and transfer everything I enter in my fields to the "bestellingen" list in sharepoint. The code of the save button for onselect is:

Patch(Bestellingen; 
{
Verkoper: GalleryVerkoper.Selected.value; 
'Datum Bestelling': GalleryDatum.SelectedDate; 
Klant:GalleryKlant.selected.result; 
'Aantal Rieten': Value(GalleryAantal.Text); 
Stier: GalleryStier.Selected.result; 
XX: GallerySexed.Value; 
Prijs: Value(GalleryPrijs.Text); 
'Rieten korting': Value(GalleryKorting.Text); 
'% Korting': Value(GalleryPercentage.Text)
}
)