If you are extract brewing the only thing you need to worry about with your water is making sure there is no chlorine, or cloramine in it. Water chemistry is more to do with ph in the mash and the sulfate to chloride balance to accentuate hop or malt characteristics. The extract producer has done the mash for you.
Just my thoughts but I wouldn't worry about making much if any water adjustments for extract brewing. Except of course, make sure you deal with chlorine/chloromine. A campden tablet, even half of one will rake cate of that. Alternatively you could purchase spring water from the store.
A game changer for improving beer that may make more sense for you now, may be controlling fermentation temperature if you don't already have that. If the yeast you are using has an upper temperature limit of 20C, and you are fermenting in a room that is 20C, the temperature in the fermenter could get as much as 2-4 degrees higher than that. This will negatively affect your beer flavor.