The cab rotates round on the slew ring - this needs greasing every 50 hours via a grease nipple located on the front or side of the machine (it may be highlighted by a sticker with an icon like a small cog next to a larger cog) You grease it by applying at least 5 pumps of a grease gun into the nipple at every 90 degress of rotation (4 times throughout the 360 degree rotation)
The machine most likely will have a gear oil resovoir (especially if the excavator has two speed tracking) on each of the track motors - Will probabaly need changing every 500 hours, not easy to describe how to change the oil though!!
Sorry I can't be more helpfull.
Best get a service manual if you can.