you have placed the ends of the wires into the connector
you'll need to use the crimping device. Simply insert
the wire into the device, and pull down. Make sure that
each metal connector has gone into the wire enough to
make a connection, if not simply pull harder. Repeat this
step for the other end of the cable.
If you're so inclined you can use a loop back tester (also
known as a category 5 cable integrity tester) to check
the cable for problems, though this will cost you some
money. Using one of these is only recommended if you are
going to be doing a large job involving A LOT of cable.
One of these devices can run you upwards of $100.
You may not be able to get this to work correctly the
first time around, but don't fret. Make sure you do buy
more cable than you actually need, as you'll want to leave
room for error.
more information on building your own home LAN you may
want to check
out the guide I wrote for Sharkyextreme.