First of all welcome to the forum, you will need to heat up the soldering iron then wipe the end on a damp sponge to remove the excess solder that will give you a clean tip.
You don't have to heat up the metal first just make sure they are in the right place and clamped together then rest your solder where you want to apply it and touch it with the iron, that should melt it and hopefully leave it where you want it
You can also buy a holder for your soldering iron and they usually have a sponge in then, if you plan to do a lot you might also want to buy a solder sucker, it's like a pen and when you heat up the solder it will suck it up for you so you can remove what you don't need.