You will find the 'pencil anode' in the end of the heat exchanger, that is the end where the two rubber hose connect.
The other you will locate in the engine oil cooler, this time in the end which does not have the hose connecting.
Both anodes will be visible by locating a square end plug, unscrew this and see the anode on the other end. The plugs have a tapered thread, so should require little if any sealing when you replace them.