hopefully you have a soldering iron and not a soldering gun
be sure the soldering tip stays tinned and clean
first, tin both the pot and wire individually
the wire should tin fairly easily, but the back of the pot make take a bit longer but not much longer. be sure not to over heat it. if the pot cover is just not tinning, make sure the tip is tinned and the pot area is clean. apply a small amount of solder to the tip and try again.
once the pot starts to accept the solder, apply a bit more and create a small spot of solder
now both parts are tinned, dab the pot solder spot and get it molten and then lay the wire on it between the iron tip and pot's cover. solder should now flow onto the wire.
you're done.
be sure not to over heat. if solder is not flowing in a matter of a second or less, there abouts, remove the iron tip.
don't blow on it to cool it.
keep the tip tinned and clean
I like 700 degree tips but 800 will work, but it depends.
a conical shaped tip end may be more difficult to use. I like a small screwdriver tip end for this type of work.