I suggest looking up a more detailed guide on how to solder to contact pads to learn more, but here's the gist:
Start by "Tinning" both the ends of the wires and the pads you wish to connect to. This is essentially just applying solder to them. You do this by holding the solder and soldering iron to the PAD OR WIRE, don't let them touch. Once the iron heats up the wire or pad enough, the solder will be melted by the wire/contact pad. Never hold the soldering iron on for more than about a second and a half onto the contact pads. You won't need more than that to heat the pad up enough to melt solder (Pay attention to ensure you don't get solder on any other contact pads in the process; this will short your system when you turn it on and can do many things from causing errors trying to boot to frying your system). The wire, may take a bit longer, and will not be harmed by a bit more heat.
Once both the wire and the contact pad have some solder on them, simply bring the end of the wire to the contact pad and apply a very small amount of heat to get the solder of the wire and the contact pad to come together.
Like I said, you could probably benefit from watching a tutorial on youtube as well or something. I'm not an expert, I just know what I do from a couple years of hobby soldering.