How can I define custom columns for collect function in Power Apps?

Question

I would like to create a collection from a Sharepoint list in Power Apps. The list contains specific columns which I defined before. But when I add the Collect(mycollection, mySPlist) function as OnStart action I receive a lot of useless column as can be seen in the linked picture. For example "Created date", "ID" even some "table value" like Author.

Of course I cannot process a collection like this because I can't ignore the irrelevant columns when I'm adding a record via some TextInput field. My intention is to update my Sharepoint list with my collection gaining the added records.

The main question: How can I define a collection with custom columns on starting my app?
Thanks for your advices.

Answer 1

ForAll('source' As item,
   Collect(collection,{
     col1: item.Column,
     col2: item.Column2
     })
  )