You can simply melt the solder and blow it out of the hole like you were
blowing out a candle only use more force. You can get an old towel and
use it to prop up the gadget you're working on, hold the wire lead
in one hand the soldering iron in the other then if you have solder on a
spool, have a piece unrolled a bit so it sticks out from the spool then
you can tin the stripped end of the battery lead wire with solder by
touching it and the solder to the iron at the same time. You don't need
more than a tiny amount of solder to tin the short stripped end of the
wire lead. If you have solder in a plastic tube, pull out a few inches
of solder then hold the opposite end of the tube in your teeth like you
would the plastic cap of a ball point pen. Proceed with tinning the
stripped ends of the battery leads. The solder in the stranded wire
makes it stiff enough to hold together so it can be stuck through the
previously cleared hole in the circuit board then bent over enough to
stay in place or with your gadget propped up by folds in the old towel,
melt a bit of solder on the tip of the iron then holding the wire lead
with the fingers of one hand, push the tinned end of the correct
polarity battery battery lead through the hole in the circuit board then
touch the tip of the iron with tiny blob of melted solder to the tinned
lead and printed circuit board where it sticks through at the same time
and the solder will flow off the tip of the iron to to make the
connection. Don't hold the iron on the circuit board for than a second
or you may burn it. Hold the wire steady in place for a few seconds
after melting the solder and the connection will cool enough for you to
let go. I do this kind of stuff without thinking because I've done it
for so many years and even I can screw up so be safe, don't lose focus
and concentrate on what you're doing or you could damage something. I'm
sure there must be a YouTube video on soldering
wires to a circuit board but if you have any questions, don't fail to
ask. ^_^
P.S. I know you can handle it. ^_^
TDD