for the electric start to work,there must be a battery on the bike.id say the battery is pretty knackered and theres only enough juice there to make the solonoid click rather than spin the motor up.
find where abouts the battery is located on the bike,normally under the rear number board plastics.get a multi meter across the battery and check the output with engine off.battery should read 11-12 volts.check with engine running,should read 13-14 volts.
if the battery is good then its either a dodgy earth,starter motor is funked or starter relay is funked.
check all earths ect are clean,rust free and tight.
to check starter solonoid.power on,multi meter red to starter motor feed on solonoid (thick red cable) and meter black on battery neg (black).flick starter button and your meter should read 12v.