Welcome to brewing and thbf..
Time and gravity will clear the cloudiest beer
With a kit brew the 'particles' are the yeast which have done their work for you billions of the little feckers. as their food supply (sugars) is exhasted they go dormant and drop out, but being so tiny it can take a bit of time..
The thing about kit instructions is that they are generally visible on the kits packaging and are therefore an aspect of its marketing. Consequently the kit that looks the best on the shelf to a newbie brewer is the one that puts a beer in his/her hand asap
WE ALL FELL FOR IT!!!!!!!
However the lucky ones amongst us either found a site like this, or in my case was too lazy to pour the beer down the drain after my first sup 20 something days after starting, and then when coming accross the bottles some months later and feeling brave gave it a 2nd sup and was bowled over by the difference..
PATIENCE is the hardest skill to acquire with brewing, But well worth it as when you give the beer the time it needs to mature its flavour properly you will be rewarded with a sup you can be proud of
You can leave beer undisturbed in its FV(fermenting vessel) for weeks n weeks without worry, Months even, after 6-9 months its possible that some dormant yeast can awake and go cannibal which can theoretically impart an off flavour, and any dry hop additions can go a little grassy if left to steep for too long. But 2-3 weeks in the FV or even a week or two longer is nothing to worry about..