If your lawn is more weeds than grass, then I would just kill it with glyphosate. You will need to water weed, till and repeat until you have moved up most of the weed seed and you no longer see as many weeds coming up. Get a soil test if you can. It will tell you about the pH and nutrients that are in the soil and if you ask for recommendations for lawn, it will tell you how much fertilizer you need to add when it is time.
Add 4-6 inches of a blended compost on top of the lawn. You can add organic fertilizers like manures, but I would wait for the soil test to find out how much and what kind of manure to use. If you get snow early, then just cover everything in a layer of straw mulch and let it sit until Spring. The compost and organic fertilizers will release very slowly over the winter as microorganisms slow down a lot. But, next year when you dig in the straw mulch, you can do one more round of glyphosate if there are surviving weeds. Add the fertilizer recommended by your soil test 4 weeks before you plant your new grass so it will get a good head start. If you are using grass seed and not plugs, stolons, or sod, then wait a month before applying a synthetic nitrogen fertilizer.
Prepping the soil willget rid of most of the weeds and organic matter will improve soil tilth and feed the soil web. Organic matter will help the soil to retain moisture and provide a good foundation to establish roots. Getting rid of the weeds and as many seeds as you can beforehand will mean fewer weeds to compete with the grass later.
Grass is hungry, it needs regular water and new grass will need to be fed monthly. Look at the label instructions for how often you need to feed on the packaging. Organic fertilizers will need weekly supplements while the grass is in active growth.
Happy gardening in Hawaii. Gardens are where people grow.