As far as the screws, those are to reinstall the sling loop from the ACR stock.
https://images.app.goo.gl/iPzVTYo4268XpoqcA1- Drive out the roll pin from the ACR stock to separate the ACR rifle interface and the stock frame.
2 align hing of the Bren/ACR adaptor with the ACR stock frame. And drive the roll pin back.
3 There are two components of the Bren 805 stock. Part #29 will be reused. The 805 stock frame is separated by pushing the disassembly button and push the stock up
4 install the acr stock by sliding it down
