You can get the manual for the RGB745 at the GE Appliances support site: http://www.geappliances.com/service_and_support/literature/
. Enter the model number in the search box. There are several models that start with RGB745.
On most of the Hotpoint ovens for regular baking, press Bake and use the + or - buttons to set the desired oven temperature. Then press Start/On. Then the oven will display Pre as it re-heats. When the thermostat indicates the desired temperature is reached, the oven will beep. The racks should be on the middle positions for most baking. (For roasting use the lowest positions.) Put the food in when the oven is done preheating. When done, press Clear/Off. Timed baked requires the clock be set correctly, then set the start and end times.
For the older ovens with dials to control the oven, set the first dial to Bake and the second to the desired temperature. Wait at least 10 minutes for the oven to preheat. Again put the oven racks in the middle of the oven for most baking.
Do not lock the oven latch and keep the oven closed through the baking cycle as much as possible. (Rotating pans and basting steps should be done quickly so that the oven doesn't cool much.)
I hope this helps.