Bringing the internet to a dependency

Good evening everyone,

I have a project to bring internet via an Ethernet cable from my box in house M to a dependency D that serves as my workspace/leisure area.
I started by drilling holes in the walls between M and D through which I will run Category 6 internet cable in ICTA conduits.
On the house side, I’m installing a male RJ45 socket that I will connect to the box.
On the D side, I would like a way to distribute the internet to different devices (there’s only one input in a female RJ45 socket).
This is where I need clarity on the most appropriate equipment:

1/ What is the purpose of a patch panel? Is it an essential component?
2/ If I connect a switch to the wall socket, and then connect the other wall sockets in each room to the switch using Ethernet cable, will that effectively distribute the internet to each socket?
3/ If I connect a switch to one of these sockets, will it allow me to plug in multiple devices (TV, game console, Blu-ray player, even a second computer...)?
4/ What type of cable should I use to connect the different devices: straight or crossover?

Thank you for the answers you will provide to my questions.