The idiot's guide to linguistic morphology

Hellllp, I just don’t understand this branch of linguistics at all. I’ve looked up the article on Wikipedia but it just seems like a disjointed cavacade of information that don’t relate to each other. Can someone explain it to me in layman’s terms?

Oh and also, where is the dividing line between lexis and morphology? Things like determiners I thought went into lexis but noooo, apparently I got told they go on morphology.

Big words are made of little words, prefixes, and suffixes.
There are several ways to do this.

Derivation is IMO the easiest example of this. Take the word create. It’s a verb. Let’s say I want to make a noun to refer to someone who creates. I add the suffix -or and I get creator. Let’s say I want to make a noun to refer to the action someone makes when they create something. I add -ion, or -tion and I get creation. Want an adjective that describes someone who creates? Add -ive and get creative.

Morphology is basically the study of putting together these little ‘morphemes’ i.e. root words, prefixes, and suffixes. It can also refer to inflection, which includes conjugation, as in, I need to change the verb ‘to create’ depending on grammatical rules of tense and agreement. I create, I created, he creates, are all based on the same root idea, but have morphemes added to them.