Our tractor is a Romanian Uzina Tractorul Braşov model U-445 and weights 1480 kgs. Needless to say it isn't very common in Australia.
Same as a car, you can use car coolant but water is just fine.
When the water is muddy (like above) warm up the engine a bit and drain the entire system via the drain then refill with clean water.
Same as car, refill at top of engine, check levels via dipstick. When oil is thick and very very black do an oil change otherwise just check the level and top up with standard diesel motor oil.
Gear Box Oil
Check level via dipstick, refill via marked nut top left from the gear stick. Use same oil as used in engine (standard diesel motor oil).
If the inspection window area becomes very cloudy or muddy then it's time to replace the filter.
Each back wheel hub require their own oil. Top top nut can be undone for refilling. The middle nut is for level checking (stick finger in and oil level should be just below the hole). Fill until oil starts coming out the middle hole. The bottom hole is for draining. Don't use motor oil, use gear oil (e.g. 85W-140).
Tractor has a dual stage clutch. Press until first resistance is for changing gears. Press fully until mechanical stop to engage PTO clutch.
How to slash
To do slashing move the PTO lever to the left to ensure slasher gets the power it needs. Keep the motor revs around 2000 (white outer markings) or PTO revs around 550 (red inner markings) and tractor in first gear. If going too fast revs can be lowered but better to use clutch and brakes to control tractor speed to keep the PTO revs constant.