Trees and plants in the wild are watered by rain. Don't use the stuff out of your tap/faucet. Chlorine is great for killing off bacteria in stagnant water in pipes and so on but not so good for your plants. They don't care about Legionnaires etc that kills us lot off. Your plants want the raw stuff out of the sky so get a water butt and feed it from your house roof.

In the wild, plants are not surrounded by walls, floors and ceilings. They are, however, surrounded by other plants and trees that are trying to out compete them for the basics - water and sunlight.

Indoors the basics are: Water: rainwater only, unless it runs out then tap for a few days at most. Moist but not wet. Light: Some but not direct all day.

Now, some plants prefer more or less eg a Venus fly trap prefers constantly wet roots and direct hard sunshine. A orchid might like 7-14 days of drought and then a good dampening for a day or so (never static water).

It really isn't rocket science. You just have to remember that plants never evolved to live inside houses. Your mate that said "For watering guidance ..." is spot on. Just make it rain water and not tap if you can.