Firstly you can download a replacement manual here, you will need the model number of the oven which should be on the ID plate found at the rear of the oven, and also on the rim of the oven as you open the door.
If the clock is flashing this rather depends on the model of oven you have, however most have a button you can press below the icon of a clock, pressing it once should stop the time from flashing, at which point the oven\grill should work. Instructions for setting the clock can be found in the manual you can download above.
Please let me know if you need anything clarified, and where possible please provide the model number of the oven
I haven't heard from you in the last few days, please let me know if you need any further assistance, if not I would appreciate if you could rate the service received.