Table borders keep reappearing

Hello,

I need to format a table to APA 6 format. It should look like:
https://imgur.com/mrFkceR

At the moment, it is looking like:
https://imgur.com/2S0htkT

Attempts that I have made:

  1. Removing all borders, then selecting the rows that I need and applying borders to them.
  2. Removing all borders, then selecting the cells that I need and applying borders to them.

At first, everything looks fine. But if I were to close the document and reopen it, extra borders would appear again. Does anyone has any idea on how to fix this?

(edit: activated screenshots -AK)

It’s simple!

  1. insert new table
  2. select whole table and right-click on Table properties
  3. go to Borders tab and remove all borders
  4. select only first row of the table
  5. go right-click and Table properties
  6. in Borders tab, add border at the very top of the box displayed there and at the very bottom of box displayed there

That should work. Accept this answer if I answered your question.