Did the seed germinate?

Some of the answer depends on where you live and what kind of grass you have. So in your next reply, please give us a little more info. Also how much of the lawn is under trees or in the shade?

We can fix your newbieness. Here's a start.

Watering: Deep and infrequent is the mantra for watering. This is for all turf grass all over the place. Deep means 1 inch all at one time. Put some cat food or tuna cans around the yard, and time how long it takes your sprinkler(s) to fill all the cans. Memorize that time. That will be the time you water from now on. My hose, sprinkler and water pressure takes 8 full hours to fill the cans. Your time will likely be less. I like gentle watering. As for watering frequency, that depends on the daytime air temperature. With temps in the 90s, deep water once per week. With temps in the 80s, deep water once every 2 weeks. With temps in the 70s, deep water once every 3 weeks. With temps below 70, deep water once a month. Note that you have to keep up with quickly changing temps in the spring and fall. This deep and infrequent schedule works in Phoenix and in Vermont, so it should work for you. The reason for deep and infrequent is to grow deeper, more drought resistant roots and to allow the soil to dry completely at the surface for several days before watering again. If it rains, reset your calendar to account for the rainfall.

Mowing: Most grasses get mowed at the mower's highest setting. Bermuda, centipede, and creeping bentgrass are the three exceptions. Those get mowed at the mower's lowest setting. Once you get some grass under your belt you can work on mowing heights between 2.89623546 inches and 2.862346545 inches. Some people are crazy about mowing height, but it's basically high or low.

Fertilizing: 3x per year. First time on Memorial Day, second time on Labor Day. Last time around Thanksgivingish. For the last one wait until the grass has stopped growing but has not gone full dormant yet. Unless you live in Alaska, then October was too soon for the last one.

What to do in April? DO NOT SEED. DO NOT FERTILIZE. And you likely do not need to dethatch or aerate. If you are following the watering, mowing, and fertilizing plan above, you likely won't need to do much else. In the spring (April is fine) use a preemergent herbicide to help prevent crabgrass. But if you are only watering once a month in April, you might not get any weeds. Weeds need frequent (2-3x per week) watering to sprout.

Weed and feed products don't do either one very well. There are a couple reasons for that, but to get to the point, it is much better to feed with a fertilizer (May, Sept, and Nov) and kill weeds with a herbicide (April and October).

Where do you live?

What kind of grass do you have?

How much shade?