So, this might come as a stupid question , but I do have reason.
We used to have a house with coal fire which heated the radiators, etc. so we have never experienced gas and a combi boiler. So please excuse my ignorance.

We have a Worcester 28cdi rsf combi boiler in our house. The heating of the radiators is set to come on between what seems likes ages. Possible 6am to 8pm. Which seems a lot.
So, how can we set it for shorter time to save money? (Electricity and gas together is much more than £200 a month)
In the summer when it's going to be warm (hopefully) we will just need hot water and no heating. How do I do this? Do I just switch it off, (there are loads of knobs though) or will something weird happen if I do the wrong thing?

Sorry for the silly question. We have no manual for it , and even if I did I probably still wouldn't understand exactly what I had to do to run it properly.