You remember that you have a secret admirer to meet at the park fountain at 8, but checking the wall clock looming above you like an alien observer you find you have plenty of time to experiment.
Taking off the items one at a time, you figure out what they do (or rather one tells you after a bit of faffing around and trying to guess). White sneakers create some form of barrier that makes it easier to walk on carpeted surfaces, avoid taking damage from falls, and repels mess, magnetically attracted to each other when not worn to avoid being separated. The denim jeans make you anatomically doll-like: on taking them off completely you find it mildly hypnotic to watch your crotch reshape itself, genitals and deep dark brown body hair regrowing like a very sensitive timelapse, along with your butt deepening and belly button pulling itself back into existence as your chest expands and anatomy otherwise normalizes. A chrome ring on a silvery necklace seems to ward off attention of those not under the effects of the magic clothing items, but when worn as an actual ring it seems to lose its gaze warding and has two possible effects, controlled by which way you put your finger in. One way it makes you look and feel like animate plastic with action figure joints (combined with not wearing the pants, your plastic cock seems to be constantly hard, easily stimulated, and with an angle-control joint at your balls: it can't cum but it sure feels like it does after several seconds of continuous stroking). The other way, it provides a mind-boggling wealth of information that seems to allow you to convert symbols and toys into actual things (or the other way around), create model copies of bodies, 'normalize yourself' (either suppressing transformations, or messing with history so that nobody cared abut your actions? Both could be done), and swap features with depictions, but you haven't tried it out yet beyond putting it on and finding out. The red buttoned shirt with rolled-up sleeves shrinks you to about eight inches tall when worn, and there are command word sequences that can make it bigger or smaller but it resets after being taken off.
Confident you can take the items off when you need and not get caught in a bad transformation, you put them all on with the necklace around your neck and fidget aimlessly, feeling your maleness-bulge flex as your cock would from arousal that seems to express itself through your asshole's sensitivity instead. You say "I'll get bigger" several times, feeling the stretchy motions throughout yourself as you sprout up a few inches and thicken to keep yourself proportional each time. You say it a few more, stopping when you're finally a bit taller than your original height, though still a bit thinner and with more action-figure-y muscles due to the anatomy-suppressing pants' induced proportions. Gathering the box and your personal things like wallet, keys, and phone in a small handbag (not a man purse, handbag) over your shoulder so they'll revert to normal size if separated from you or the magic clothing resizing you, with a gentle opening of the door you're off from home striding confidently toward the nearby park.
You wait at the expected place, sitting on the fountain edge for a few minutes in the evening as it turns to 8. Muttering "I'll get smaller" over and over until you're sucked, shrunk, and relaxed back down to the doll-sized 8 inches you're expected to be, it's about time they show up as you wait on the outer edge.