Heat up the soldering iron.
Touch the tip of the soldering iron to one end of the lead. Allow the lead to heat up.
Apply a small amount of solder to the end of the lead that is not touching the soldering iron. Allow the solder to melt. It should flow from the end of the lead to the trace, forming a bond between the lead and the trace. Do not allow clumps or balls to form. If they do, use braided solder wick to "suck up" the excess molten solder, and start over.
Cover your soldered connection with electrical tape.