Hiding fields in EditForm

I have made a list, made a copy of the NewForm and customized it by adding and removing certain fields to what I want.

I want a different subset of fields displayed in the EditForm, however when I open editForm to customize it in SP Designer, it appears more like DispForm, than editForm and when attempting to edit an item in the list I'm first shown displayForm and then after clicking edit Item I'm shown the default NewForm without any of my changes.

How can I change which fields are visible for editing/updating an item?

My questions is similar to this one, but I do not understand the answer. Hide some fields from EditForm