OK, so I'm going to say just be near them and make sure their water is clean 4-5 times/day. Pick them up one by one as soon as you get them and dip their beaks in the water so they take a drink. Be careful, be very, very, very careful with that heat lamp. Make sure it is dusted daily and very secure. It can start a fire in a minute. A better heater is a radiant heating plate. I know it's alot more expensive ($50-$75 probably), but it is safer. You can use it for years (chicken math). Three is a great number to start. You can use puppy pads or paper towel the first week and then you can use pine shavings for bedding (or pellets). Do not use cedar. At least 1x/day, pick each chick up and check its butt for poop. If it is poopy, take a wet paper towel and gently wipe it off. If it is stuck, then run the chick's butt under tepid water. Do not pull at stuck poop or you could tear the chick's vent (deadly). If you notice bloody diarrhea, then one or more of your chicks has coccidiosis. You'll need to treat them with Corid, which can be bought in a 16oz size. (1 tsp/half gallon of water for 5 days, wait 2 weeks and treat a 2nd time.) After a week of having your chicks, you can give them cooled scrambled eggs that have garlic, oregano, and thyme mixed in. I wouldn't hold myself to a 15 minutes schedule. Just talk to them for a minute every time you walk by as you get a chance. You need to check on them anyway. Keep it easy and fun. Your coop looks like it might be 4' x 4', so 3 chickens should be okay in it. If you have not yet bought the coop, then don't. You can easily build it for less (I'm 66 and I did). A company called Landmark on Amazon sells hardware cloth for ~$180 for a 4' x 100' roll (chicken wire is not predator proof). In the summer you want a waterer big enough to put frozen 1/2 gallon jugs of water in it to keep the chickens water cool. In the winter, if you get freezing temps, you'll want a heated waterer. I could go on and on, but feel free to message me if you want me to! Enjoy your babies.