@Kiss_Virag294
Hi,
So you've got a new home and the Archer C2 was already there when you moved in?
Were you told the C2 router has already been setup for Internet access? And were you given any password(s) with that router?
What you could try is to connect a computer via Ethernet cable to the Archer C2, then in a web browser enter http://tplinkwifi.net/ or http://192.168.0.1/ and if a login page opens try to enter username admin and password admin.
In case that let you enter the router's webpage you could then check the Wireless Settings of the router. (i.e. verify Wi-Fi is switched on and change the Wi-Fi name and password to your liking)