Help setting up a second wireless router in my home

So I have the router and modem set up in the living room. Works great.

The signal doesn't quite reach my bedroom upstairs as strongly as I'd like. I have a second router/modem I could use, but when I tried setting it up, there was no signal coming through.

Is it possible to use a second setup in my bedroom to either increase signal strength or connect straight to with my computer/xbox?

I tried googling, but everything that came up seemed different than what I was looking for.

tia