seems redundant to use rosin core solder and flux paste. I've never needed to use flux on anything with rosin core solder before. (i'm no expert on soldering)
leaded 60/40 or silver solder are both fine. I'm sure you have a radio shack near you. if you do their solder is very good.

tin every part you plan to solder together even the wires. that's the secret. tinning is melting solder to the parts before they're soldered together. you'll have joints that look like a pro did them.