I'd start with a Google search and find a copy of the Owner's manual for your stove.....when I got my current boat there was no manual and I couldn't figure out how to get the pilot light lit so I Googled "mariner princess owner's manual" and got the info I needed. Hopefully that's all you need and you won't need a new thermocouple or anything like that.
I light my oven with a butane lighter (the ones for lighting outdoor grills). Have to hold the light button down while I get the pilot light to catch. The instructions for lighting the oven (the right way, not my way) are posted inside the top of the oven door. Maybe your oven has instructions posted to it in some obscure location.
My oven is equipped with a battery operated spark generator. Maybe the electrode for the oven is defective or dirty.
Like in a car that won't start, its either no gas or no spark.
Turn off the gas, ignite the top burner to clear any gas from the line.
Try lighting the oven several times. This is to clear any gas in the lines.
Look in the oven for the spark that lights the burner.
The Force 10 with thermostatically controlled oven has two buttons. The spark button, which makes both stovetop and oven/broiler electrodes spark, and a safety button for the oven/broiler only. To light the oven, set the temp you want, push and hold the safety button, then push the spark button til the oven burner ignites.
Usually our problems are when something gets dirty. If you lay a 12" X 12" unglazed tile on the thin stainless above the oven burner it will burn your food less. The tile will break but don't worry about that.