Hi,to the OP. you may notice,that on your original fitting base plate,you have three sets of terminal groups. You also have one set,at the top of the picture,for the earth cables.
This makes four separate "gatherings",of conductors.
You may have also noticed,the "chocolate block" type connector,in your other picture,has only three.
For this,and other reasons,you may struggle to get any professional spark,to walk you through a job such as this.
It's Christmas,and if you were me neighbour,i would do this for a brew & a mince pie
Get a spark in and have a good Christmas