Most bow ties these days fasten with a hook and eye.
If you want to TIE a (proper) bow tie you will probably need a lot of patience and practice. The procedure is too difficult to explain without pictures so check out these two links.
http://www.bowtie.com/tying.html
and this one
http://www.formalwear.org/public/resources/bowtie. html
both give clear guidelines with diagrams.
When you do find a diagram to help you, it's a good idea (believe it or not) to practice tying it round your lower leg to start with instead of your neck.