Put the two end posts up and then use the first(top) wire or a string to line up the holes of the rest of the posts. I put them 4 paces apart. Horses get horse fencing or barless wire. Cattle, goats, sheep get a barbed fort. Deer get horse or orchard fencing.
Ok, you want to build a fence to keep your horses, dogs, kids in. With horses the fence needs to be within a horse neck of the road. They have a tendency to lay the fence over if there's a lot of feed along the roadside and they can't reach it. You will not have to mow. People will not have room to park there and ignite the weeds with their exhaust. If you have dogs and kids you can pull it back a little but the parking in weeds is still a problem and you'll need to mow or weed eat along it so make it easy to access. Fence goes up once, mowing happens every year. Also every bend has to be braced, you have to build straight lines. If you have a map of the parcel or lot, the fence gets drawn in with a ruler, not free hand or with a compass.
Be careful not to move the string as you put your posts in. Height doesn't matter at first, I use chin height against the tamp. When you clip your top wire you can tamp down the ones that are way too high.
Again, string the top wire first, use it to even the top of each post by clipping the wire on the low posts first then lowering the other posts and clipping the wire on them last.