Good question and nice to see that someone is reading.
A particle forming is the beginning of order, non-random. The particle is made of randomness, yet is, itself order, because it does not move randomly, only its constituency does: “Order rises from chaos”.
Technically that kind of event (defying the Second Law of Thermodynamics, is called an “attractor”. But the word “attractor” is misleading because nothing is actually being attracted, but rather entrapped. The random tiny portions of affectance flying all about (“afflates”) get slowed/delayed like flies in molasses when they inadvertently run into a particle. They eventually find their way back out, but in the mean time, that point in space, the particle, is getting hit from literally every direction and thus doesn’t move (much) and becomes a tiny point of order (the First Church of Random Affectance). Traffic jams on highways and crowd at theaters are similar. The traffic jam or crowd is relatively motionless, yet made of smaller moving objects.
So the particles that form the matter are not themselves random, quite the opposition to randomness. But each and every one of those particles is formed from random affectance getting delay, like your paycheck in a bank. The particles are, moment by moment, releasing and acquiring new tiny bits of affectance.
That delaying of affectance is merely because affectance is running into affectance. Radio waves will actually very slightly delay other radio waves, especially if ultra high frequency. Light slows light, because affectance slows affectance. And that process causes a particle, a center of high concentration of affectance, to acquire a more dense surrounding of affectance that gets gradually less dense further away. That surrounding ambience is the particle’s “gravity field” or mass field.
The reason that such particles will begin to move is simply that each particle will acquire more affectance from whichever side had more affectance density. If there is a lot more affectance on one side of the particle than the other, that is the side that the particle gains more affectance from and thus as it reconstitutes itself instant by instant, its center is slightly shifted more toward the more dense region. And between two particles the affectance density will be higher than anywhere else around them. Thus they keep reconstituting closer and closer to each other, blind to the fact that the other particle(s) even exists.
I thought that I had made a sketch of two particles moving together, but don’t seem to be able to find it. 
Positive vs negative particle in the ocean of affectance:
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