Switch the dial with the radiator symbol to On for constant heating or to the Clock for heating at times chosen on the 'daisy wheel' timer. Have you set the thermostat in the house to a suitable temperature?
The 'daisy wheel' timer is very good when you turn the little dial to the clock setting.
With your fingernail turn the big hand in the clock to the right time in the direction of the arrow. As you turn the big hand the little black triangle on the big ring will turn to the time on a 24 HR clock. Make sure the triangle is at the right time eg 5 am or 17 pm.
Then to get the boiler to work at chosen times, push the tiny little 'daisy wheel petals' in to the numbers. The numbers they are pressed in for is when the boiler is on. Note 24hrs again.