If your rear wheels start spinning try to get more weight in the back if possible. If all else fails then you’ll have to do a burnout to get the tires hot so they will stick to the ramp better.

Give it gas and hold the brake a little too so you won’t slide back into the water. Give enough gas to get the wheels spinning real fast but don’t over rev your engine. Watch the RPM meter to make sure it doesn’t redline. Shortly your vehicle should start inching forward up the ramp. If you’re still not moving then let off the gas and hold the brake. Then slowly give it gas trying not to burnout. If all this fails then you’ll need to find someone that’s capable of pulling you out.