Going to try my hand in wine

Have been making cider now I would like to try some wine was. Going to pick up some peach,strawberry, and pear juice this weekend pretty much have the basics down I think just have a couple questions how much sugar should I add if any to 6 gal carboys and what type of yeast should I use would like to keep the wine sweet

Use a hydrometer to measure the amount of sugar needed, 1.080 - 1.090 will get you a nice soft wine, much above that and the alcohol will overpower the fruit for a long time.

Yeast choice is very subjective, look at the manufacturers websites and pick one that sounds like it enhances the flavor you are looking for.

You won't be able to "keep" the wine sweet, you will let the yeast go until it can't go any more, stabilize and add juice or sugar back until it is sweet enough (actually, it will be slightly less sweet than you want, but it gets sweeter with time). You can't stop an active ferment very easily.

Other than that, have fun!