PSCT (Problem Solving Card Text) is a super crucial component of rulings, and is designed to be quite comprehensible. This article explains the very basics of PSCT, enough to answer the most basic of ruling questions.
Activating a card
Let's look at Chiron the Mage's text.
Once per turn: You can discard 1 Spell, then target 1 Spell/Trap your opponent controls; destroy that target.
Punctuation is very important here. The colon ( : ) after "Once per turn" tells us that this is an activated effect, not a continually applying one. This is the activation condition. Colon: Starts a Chain.
The semi-colon ( ; ) after "You can discard 1 Spell, then target..." denotes a Cost. We need to pay this cost at the same time that the effect is activated. Semi-Colon; Cost.
Finally, the rest of the text is the effect itself. This happens on resolution. In this case, we "destroy that target".
An example of something which doesn't have an activated effect is Banisher of the Radiance.
Any card sent to the GY is banished instead.
● There is no colon to be found in this psct, so this effect does not activate.
An example of something which doesn't have a cost is the Trap, Paleozoic Dinomischus.
(If this Trap is activated): Target 1 face-up card on the field; discard 1 card, and if you do, banish it. ● When activating this card, you only read until the semi-colon, so all that happens is targeting.
● Only when the card resolves do you discard - and if you do, you banish the target.
This is basically all you need to know in order to understand the basics of PSCT. MikaPSCT takes it a step further and denotes things such as conditions, maintenance costs, lingering effects, and post-activation conditions, but those are not required for surface level understanding. Remember that not all printed cards have PSCT. Cards which never received reprints lack PSCT, so their Konami card text is practically illegible, rules-wise.
Do not confuse old card text with PSCT. Here is an example of what many people do: Genex Army - Level 6 monster. When Tribute Summoned by Tributing a "Genex" monster, you can destroy 1 card your opponent controls.
Since this card doesn't have a colon or say "target", it must be a continuous effect that doesn't target! Wrong. It is an activated effect, and does target. Why? It was printed before PSCT. How do we know that it targets, then? Before PSCT, the only way to tell was via rulings.
As you can tell, PSCT was an incredible addition to card templating - so it's worth learning.