I was given a rough guidline on my care sheet of 1 litre of water every three days, do you think that is ok?
No I don't. You cannot water your tree on any kind of schedule. You certainly cannot give a specific amount either. The quantity of water is never an issue, the frequency of watering is.
When I water, I do so copiously, allowing water to flow freely through the pot. I then wait 5-10 minutes to allow the soil to absorb and distribute that water. I then water again the same way, this ensures that the root mass is thoroughly wetted. A little water frequently is the wrong approach, I could put 2 quarts through it or 10, does not matter. What needs to be addressed is how often this occurs.
A tree in summer that is actively growing may need this twice a day, a lot depends on the specifics, texture of the soil, size of the pot, location of the tree, etc. Later as the season winds down and the weather cools, only once a day or perhaps even less. During the winter, again depending on circumstance, I may not water for weeks at a time, but always being aware of their condition.
Allow the tree to dry a bit between waterings, how much is a little more difficult to put into words. Tree roots need oxygen as well as moisture so allowing water to drain, be evaporated or used by the tree means that air then takes the place of the water which is a good thing. Observe your tree, the color of the soil will change, so will it's overall weight. Touch the soil, is it damp on the surface? If so wait another day and check again. The top of the soil can appear dry without harming your plant. In fact you should check the soil below the surface as well.
Overly simplistic instructions are probably an attempt to make a fairly complex issue more understandable for the masses. In Japan it is said that it takes years to learn to water properly. Resist the urge to water because you think "it must need it by now". When you have that watering can in your hand you hold the life of your tree as well.
Since this is an indoor tree, at least for now, the use of a humidity tray should be considered.