Heard you got one when abouts in the story is it im at the part where im just leaving the soul crain or what eva after finding the vampires mother and retriving the elder scroll (blood)

you have to be in the dawnguard and do multiple side quests for that woman who is obsessed with dwarven schematics

Don't you pretty mush HAVE to be in the Dawnguard in order to even use crossbows? I think the main idea is that crossbows are supposed to be vampire-slaying weapons. I mean, you can use crossbows outside the Dawnguard faction, it just wouldn't be practical since you would rarely ever have the bolts needed to use them from what I've read. The bolts pretty much have to come directly from the Dawnguard faction itself.

U can craft bolts at a forge. DG only.

Be in the Dawnguard, do the all the Ancient Technology quest.

you can use the crossbow on either side, DG can make crossbows enhanced or dwarven as well as enchanted bolts from the forge

You can use the steel one on either side. The only way you get enhanced ones and dwarves is if you choose to side with Dawnguard. You then have to recruit sorena (think that's her name) the lady that's obsessed with crossbow schematics You have to do her side quests to get the upgraded xbows and bolts.

If you side with the camps you can only get the regular steel one as the others will not be made because no one "found" the schematics.

^{So if you do Smithing on the Left side (Light Armor) can you not craft the Dwarven Crossbow?}

Probably not but you can still buy them from the Dawnguard woman.

You can still buff them if you enchant them though, as long as you have the Arcane Blacksmith perk.
Never a need to use more than two perks in smithing when you can always buff any kind of weapon or armour if it is enchanted.