Changing exmark hydro fliud

I have a 36in exmark turf tracer that needs the hydro fluid changed and I'm not sure how to do it I understand you pull the filter and drain the hydro fluid tank and what's in the pumps and wheel motors doesn't come out and when you put your new filter on you fill it with oil and screw it on but I read something about priming the air out of lines??? Well I don't know how to do that and when you fill you tank there's a divider in the tank I filled it to the top of the divider on both sides is that right ??? Someone told me ones for full cold fluid level and hot full fluid level well I filled both to the top of divider so if anybody knows the proper way to fully change hydro oil let me know I don't want to burn up any pumps cause it's a costly mistake any info would help