Hi @NaChristian ,
Do you want to use sharepoint list instead of collection as data source in Service Desk Sample app?
If so, you need to make a lot of change on this sample app.
Firstly, please check the columns in TicketsCollect1. You need to create the same columns in your sharepoint list.
Then connect your list with your app.
Secondly, you need to change all the controls and properties about TicketsCollect1, change their data source to your sharepoint list.
For example, in CreatenewticketPage you need to change:
1)textbox1_25,textbox1_26,textbox1_27,textbox1_28,textbox1_29
Text: CountRows(yourlistname) //please replace with your list name
CountRows(Filter(yourlistname,Status="New"))
CountRows(Filter(yourlistname,Status="In progress"))
CountRows(Filter(yourlistname,Status="Closed"))
CountRows(Filter(yourlistname,Status="On hold"))

2)Button1_1's OnSelect:
If(CreatedBy.Text="" || Dropdown_Priority.SelectedText.Priority="Select a priority" ||Dropdown_Area.SelectedText.'Account Name'="Select an area" || Subject.Text="" || Description.Text="",
UpdateContext({msg_visible:false});UpdateContext({msg_visible:true}),
Collect(yourlistname,Status,{ID:Text(CountRows(TicketsCollect1)+1),Owner:CreatedBy.Text,AccountName:Dropdown_Area.SelectedText.'Account Name',Priority:Dropdown_Priority.SelectedText.Priority,Subject:Subject.Text,Description:Description.Text,Status:"New", DateCreated:Text(Today())});
Navigate(DashboardPage, ScreenTransition.None))
//please replace with your list name

What's more, since all the columns in the original collection are all text type, you'd better set all the columns to text type in your list too. Or else you will need to change your original formulas a lot.
Best regards,