Laying network cable

Since there are two independent residential units, it should be designed so that both are separate networks. Even among family members, it is not always desired to see the other network devices of the other, and in case of possible renting out, this is even more important. However, this does not prevent you from connecting everything together now.

I would do it as follows:

Main house:
At least one LAN double socket in every main room. Possibly several connections e.g. at the TV are necessary.
Don’t forget hobby rooms and such.
At least one LAN connection on each floor on the ceiling or near the ceiling for a WLAN access point. If you use a POE access point, no socket next to it is needed.
All network cables usually end up in the utility room. There, a network cabinet is installed where everything goes. The network cables are terminated on a patch panel. A patch panel is nothing other than a network socket but with many more connections.
To supply the network cables you need a switch that is connected to the router.
Which router is used depends on your connection --> DSL, cable, fiber?

Granny flat:
You run a network cable from the main network cabinet to the granny flat. There you make a small sub-distribution, e.g. network cables to the TV and wherever else LAN might be needed in the granny flat. Currently, you could run a Fritzbox in client mode there which provides WLAN, telephony connection, and 3 free LAN ports on the FB. However, you could also do the whole thing with individual devices. If in the future you want to separate the networks, you can separate the networks with a different configuration.

I hope I am not being too forward when I recommend that you find someone to support you on-site a bit. Basically, the whole thing is no rocket science, but especially when it comes to details, you should have some knowledge.

Hello ,

hanse987 has already explained it very well. I had replied to you via PM (because of links).
I’m now bringing it back to the public area as such topics have been coming up more often lately.
Your plan is a simple socket behind the TV, a simple socket on the upper floor for an access point, and a network cable to the granny flat. There a separate Fritzbox.
In general, you should always use a patch panel. With three cables, you could also choose the (unattractive) option and simply mount a keystone module on the distribution cables. Then patch cables to the Fritzbox.
Then plug the telephone cable into your Fritzbox and run it all the way to the granny flat.
I absolutely agree with that you should lay more connections and always use a double socket...
You can easily extend the line from your telephone connection by 4 meters.
If you install your Fritzbox in the home technology room, you will mostly only be able to use the 2.4 GHz network and not the faster 5 GHz band.
Overall, you are cobbling together a network in a new building. You should find someone who knows a bit about the subject, as hanse987 recommended.
Double sockets should be in the main rooms, ceiling outlets for APs in the most frequently used areas...
The whole distribution then centrally in a small network cabinet with patch panel and switch.
Do you really want to block off all possibilities just to save 500€ now? Later opening walls is expensive...

Yes, of course everyone has a different opinion, but for my part I don't really need that. I'm not such a freak when it comes to that, as long as I have good Wi-Fi reception in every room and the Smart TV works via cable, that's enough for me for the next 30 years

If I have an access point upstairs then I would have 5GHz throughout the whole house again?

But I'm slowly understanding what I need to put together to reach the goal... From the router to the switch which is connected to the patch panel and from there all the cables go out, wherever and however many....

If you know what you need, it's really not that complicated

thanks

Just with this statement regarding the 5Ghz Wifi it shows that you don't have enough knowledge. The 5Ghz network has a shorter range and is quickly blocked/strongly weakened by obstacles. If, as you write, you want good Wifi reception throughout the house you need to plan enough APs in the right places. If you stick with 3 cables you don't need a separate switch. The Fritzbox is sufficient. The simplest solution would be Keystone modules on your 3 installation cables and then connect them to the Fritzbox via patch cable.... In the basement you will mostly be on the 2.4Ghz network since the Fritzbox is installed in the utility room. In the upper floor it depends on the positioning where the 5Ghz reception is available. If that is enough for you it would be a simple and inexpensive solution. But very suboptimal.

I have no idea either but I have already understood that it is not as complicated as I thought.

Now I am just interested to know if there are good solutions for cable management here. Should they come out of the floor and be routed to the router with a surface-mounted cable duct? Or what options are there if you want the cables to come out of the wall flush so that it looks nice?

Are you having it built?

Then you tell your electrician where the network cabinet should go (even if you don't actually put one there but only a Fritzbox) and where the network sockets should be. He takes care of it. On one end of the cable is the socket in the wall. The other end of the cable then dangles from the ceiling at the place you want.

The current - expensive - Fritzboxes can create a guest LAN on LAN port 4, which can then be connected to the port of the network socket in the [Einliegerwohnung], so the [Einliegerwohnung] is only on the guest LAN of the FB. And in the [Einliegerwohnung] you plug in another FB and let it provide normal Internet via LAN and WLAN. This is then separate from your home network.