Okay.
Gods are a type of being from another world. Each god has one or a few domains that defines them; Pelor's are sunlight, health, strength, and community. These are less interests and more fundamental aspects of the god's self; it's reasonable to say that Pelor is sunlight and health and strength and community, with the implication that things that affect those affect him as if it was his own body, or rather more so - and therefore just as a human might do anything from scratch an itch to seeking medical care for a wound, a god will react to harms to their domains. This is usually beneficial to mortals, since most gods' domains are things that are good for or useful to them and gods have a much deeper understanding of what's needed for their domains' health than mortals.
Gods, like other beings, can be categorized ethically as good, neutral, or evil and lawful, neutral, or chaotic. Good and evil are generally the more important classification, though lawful and chaotic aren't irrelevant; Pelor is neutral good. Good gods take an active interest in the wellbeing of mortals, and generally have domains that are important to mortal flourishing. Neutral gods' domains are often still important, but less directly tied to mortal wellbeing - travel, Fharlanghn's primary domain, is vital to some mortals, but others live perfectly contented lives never leaving the town they were born in, while mortals who can get by without any sort of community are vanishingly rare. Evil gods are much less common and have domains that are opposed to mortal flourishing - disease, hatred, murder, that sort of thing; the good gods oppose them.