@Marvin_S 

Wireless router Archer C7

450 Mbps on 2.4 Ghz ± 1300 Mbps on 5 Ghz

5 Gigabit ports ,2 usb 2.0 ports

3 detachable antennas

I currently have a deco x50 modem router,supplied by my provider for Fiber internet 500 Mbps. Can I use both at the same time ?

Will this extend my signal ?

If using both will extend my Wi-Fi signal. Can someone give me step by step please.

Right now my signal drops off when I am down one level ( in a small back split 1200 sq. feet ) from Wi-Fi modem/router and difficult to keep signal if in backyard.

When I was using the Archer C7 router and 25 Mbps dsl internet I had Wi-Fi everywhere. 

I don't need 500 Mbps speed and my equipment can't use that but can use 100 Mbps speed. There was no price difference from 200 Mbps fibre to 500 Mbps fibre,so decided to maybe future proof.

I can get another pod from my internet provider just wanted to use what I have if I can first.

Thanks for the help.