Extending WiFi to my garden office.

[Cashinone]

I have Virgin Hub 3 - for years an Ethernet cable serves my Desktop pc. I want to add WiFi to my office there is no signal from the house. What do I need to add to the existing Ethernet cable ?      
I was thinking a dual signal splitter to feed the pc as well as a TP Link.

Any advice please would be helpful both on method and recommendations

Many Thanks

[Cashinone]

Many thanks again Carl. I shall proceed when my tech son visits next.

[Roger_Gooner]

My recommendation is to have a different SSIDs for the WAP (which will happen anyway by default) and your devices will connect to them in the office. Once you have it working you can experiment by changing the SSIDs to what you have in the house, but I don't see why you should.

[Tudor]

One thing to be aware of is that on the 2.4 GHz band you should set the channel differently to the one on the VM hub. You can only use channels 1, 6 or 11.

[Roger_Gooner]

Yes, good advice for the 2.4GHz band. For the OP in his office his iPad and mobile phone should connect to the strongest signal which I expect to be 5GHz from the WAP and in his house 5GHz from his hub (at short range but could be 2.4GHz at longer range or through walls and other physical obstructions).

[Tudor]

Yes it would certainly be better to use the 5Ghz band and unless you want to use the 2.4Ghz band outside in the garden (maybe it will stop raining sometime!). I would probably just turn off the 2.4Ghz signal for the moment. The WAPs I use, UniFi AC Pro ones, reach right to the end of my garden even on the 5Ghz band.