The seed packet came from a hardware store that also had, for some reason, a whole rack of Halloween decorations still boxed up by the register in March, left over from a season five months gone.
Your first day
Buy a packet of radish seeds and, for a pot, a bag of potting mix, and plant in spring or fall since radishes bolt in summer heat. Pick a spot that gets at least six hours of direct sun a day, since radishes sulk in shade. Loosen the soil in a small patch, or in a pot at least half a foot deep with drainage holes. Poke holes about half an inch deep, two inches apart, and drop one radish seed per hole. Cover lightly with a pinch of soil and water gently, with a spray bottle or small jug, until the soil is evenly damp, not pooling. Check daily: until sprouts appear, top up whenever the surface starts to dry, then water only once the top layer feels dry to the touch.
Most beginners overwater out of anxiety, checking constantly and adding a little more water just in case. Don't. Far more seeds rot from too much water sitting around the roots than ever die from too little.
The thing most people miss
Radishes are ready to harvest in under a month, which means a complete result comes fast and a mistake shows up while it still matters, instead of after an entire season. That was the case against reading up on soil chemistry and plant biology first.
After that I stopped researching extensively before planting anything new and started just planting something fast and cheap to fail with, learning from the dirt itself rather than from another article.
How you'll know it's working
Small green sprouts should push through the soil in nearly every spot you planted a seed, usually within about five days. Counting them against how many seeds actually went in is the real tell, not just that something came up.
My neighbor, who'd been growing tomatoes in the same yard for years, seemed almost surprised I hadn't killed the radishes, which told me more about her own early attempts than mine. Succession planting, staggering new seeds every couple weeks instead of one single batch, is worth trying next so the harvest doesn't all land in the same week.