What is a particle?

I posted this elsewhere also and just found this place so copied it down but yeah. I've always wondered this cause I like wondering bout things but I wanna know and it's simple so I should. I got an idea of it I think, from what I understand particles are points of interaction? Kinda like how light is a wave and a particle.

Does it work in the sense that the light is a solid uninterrupted 'string' of sorts (just a rough way to put it but only way i know lol) but when it hits something and is absorbed or whatever else the 'head' or leading bit of the wave that's interacting with the object is the photon, which is the particle form of light (i think)? Not a string of particles on it's own just travelling through space, just solid and not chopped up, but can be viewed as particles when it's colliding and interacting with an object and the photon particle is the collection of qualities of that exact 'slice' of interaction between a wave and another thing?

If that's how it is, is that also what they mean by the whole observation collapsing wave functions and making reality deal or however it'd be worded? Just observation as a substitute word of sorts for interaction? Two waves or 1 and an object or whatnot interact, and the points they interact at stand out or are distinct from the rest of the wave(s) as a background of sorts, and those points of interaction/observation are what can be 'noticed' by everything and that's how observation 'creates' the universe as it goes along?

Could have one universe with two waves of light just travelling side by side for eternity and never touch and not fully but in a sense you'd never have any universe, in the sense that there wouldn't be any way at all to tell there's anything there because there's no interactions that could be 'measured' to tell you anything about those two waves. But could have another universe where it's two waves of light heading straight to eachother on course for a head on collision, and when they interact reality is 'created' in the sense that an observer could watch and record the interactions/particles that result as they meet, and since the qualities of a thing are only the result of the way it reacts to other things (like somethings red because it eats green and blue wavelengths and says no to red), you would then have a reality or universe created in that things could be described.

this is all just me guessing because I can't ever find anywhere that'll give me a good answer, so maybe you all can say yes thats what it is or correct me if it isnt or whatnot. thank you