Hello! Well you have arrived where I was in July. You have the right idea but bad timing. It's too late to kill it all off and reseed. Your seed won't make it through the winter and it will just die out.

your not going to like what I'm gonna tell you but you need to wait till next August and use round up on your whole lawn.

Then look into mowing bagging, dethatching fertilizing adding macros etc. next summer

I know it sucks to wait but now you can get a soil test and send it to Logan labs to get an analysis of your lawns needs. ( mine for instance needed 125 lbs of lime per 1000 sqft! So I spent last winter correcting the pH and the next spring killing off any grubs with dylox and long term grub control with Merit.

oh and it is possible to go from terrible lawn to a nice lawn here's my before and after. Good luck

Noobs generally are off by several months in timing their lawn projects. Most are off by 6 months, so you're way ahead of the game. You're just off by 2 months. There is a thing called frost seeding where you put the seed down after there is absolutely no chance of any of it germinating this season. Usually that is December of January. That seed will germinate early in the spring and give you a half a shot at having a lawn last longer than July. Most spring seeded lawns die out from the summer heat leaving behind crabgrass...and the weeds you already have. That's why darktower suggested waiting until August.

You might be able to kill off your weeds with a spray using Weed-B-Gone Chickweed, Clover, and Oxalis killer. It's a stronger formula than the traditional WBG. If you have grass still in there the WBGCCO should leave it alone.

Since you're a noob, here's the 1-2-3 of lawn care as I have put it together after many years reading many forums.

Basics of Lawn Care

After reading numerous books and magazines on lawn care, caring for lawns at seven houses in my life, and reading numerous forums where real people write in to discuss their successes and failures, I have decided to side with the real people and dispense with the book and magazine authors. I don't know what star their planet rotates around but it's not mine. With that in mind, here is the collected wisdom of the Internet savvy homeowners and lawn care professionals summarized in a few words. If you follow the advice here you will have conquered at least 50% of all lawn problems. Once you have these three elements mastered, then you can worry about weeds (if you have any), dog spots, and striping your lawn. But if you are not doing these three things, they will be the first three things suggested for you to correct.

1. Watering
Water deeply and infrequently. Deeply means at least an inch in every zone, all at once. Infrequently means monthly during the cool months and no more than weekly during the hottest part of summer. Do not spread this out and water for 10 minutes every day. If your grass looks dry before the month/week is up, water longer next time. If that does not work, then you might have to water more than once per week during the summer's hottest period. Deep watering grows deep, drought resistant roots. Infrequent watering allows the top layer of soil to dry completely which kills off many shallow rooted weeds.

You will have to learn to judge when to water your own lawn. If you live in El Paso your watering will be different than if you live in Vermont. Adjust your watering to your type of grass, temperature, humidity, wind, and soil type. It is worth noting that this technique is used successfully by professionals in Phoenix, so...just sayin.' The other factors make a difference. If you normally water 1 inch per week and you get 1/2 inch of rain, then adjust and water only 1/2 inch that week.

2. Mowing
Every week mulch mow at the highest setting on your mower. Most grasses are the most dense when mowed tall. However, bermuda, centipede, and bent grasses will become the most dense when they are mowed at the lowest setting on your mower. In fact there are special mowers that can mow these grasses down to 1/16 inch. Dense grass shades out weeds, keeps the soil cooler, and uses less water than thin grass. Tall grass can feed the deep roots you developed in #1 above. Tall grass does not grow faster than short grass nor does it look shaggy sooner. Once all your grass is at the same height, tall grass just looks plush.

3. Fertilizing
Fertilize regularly. I fertilize 5 times per year using organic fertilizer. Which fertilizer you use is much less important than numbers 1 and 2 above. Follow the directions on the bag and do not overdo it (unless you use organics in which case you may overdo it without fear of hurting anything).

At this point you do not have to worry about weed and feed products - remember at this point you are just trying to grow grass, not perfect it. Besides once you are doing these three things correctly, your weed problems should go away without herbicide.

@Darktower00844 I didn't know you could send in soil to get it tested, is this a very expensive option?

As for general care I would say let the grass grow longer and then cut it, rather than keeping it trimmed short consistently. If you want a quick fix, sod is good, however it can have a patch work look to it. Otherwise I recommend grass seed, loosen the soil, mix the seed with some compost and then spread it on your lawn. Use a rake to get an even spread. Then water it about twice a week when the sun is low for about 15 mins.

Nope Logan labs it's like $15-20 but it tells you everything you need to know. Look them up and follow directions. Start this process now so when it's time to seed your soils are ready.