Q.will the salt and water hurt the grass?
I’m trying to get all those weeds out of my grass, those little ones with yellow flowers on top, or those other fuzzy ones, too many to try and pull out. I would like to try the salt solution, but will it kill my grass?

Salt can be used to kill weeds, but it would be difficult to direct it to just the weeds. If splashed onto other vegetation that also most likely would be killed.
The most common way to keep your lawn relatively weed free is the use of a weed and feed product.
I have listed a few links for you that may be of help and help your lawn!
https://www.gardeningknowhow.com/special/organic/using-salt-to-kill-weeds.htm
https://www.gardeningknowhow.com/lawn-care/lgen/lawn-fertilizer-tips.htm
https://www.gardeningknowhow.com/special/organic/homemade-pet-friendly-weed-killer.htm