I'm 73 & fenced by myself. We're in Virginia. There are 100+ ways to fence but I did it like here with 1 exception. I used tractor & auger (Danuser w/9" auger&spare bit & cutters).
If you have that...no big deal.
I ran string line on property lines. Only help was my wife I had long pole & a good rifle/scope (yes...unloaded)

. Pole had a level on it. She would hold it & I'd guide her L&R...then stick in ground mark.
Then stakes & string. Start at corner, auger down 2-3ft with PT 9s. go out 10ft each way & auger & another PT9. Then a PT5 w/ galvanized dowel...everything straight&level (level ground)...then X'd heavy galv wire & ratchets.
Now I had starting point.
Then all fencing a PT9 every 50ft, four 7ft heavy T posts between every 10ft. Then red-top woven wire. I wired up a foot (we have horses...they're not going under 1 foot & bush hog can mow under. I wouldn't want even galvanized wire touching the ground.
Every transition I used 3 posts, even a small angle.
Now wire. I used two 2x4s holes drilled & carriage bolts, washers, nuts. Use fence for guide. Idea is clamped tight to wire fence now with come-a-longs & ratchets I pulled so tight you could play a tune on it. Galvanized staples hammered in.
Corner posts I poured in quikrete. Others a 7ft tamping iron. T posts pounded in w/ tamper (good exercise).
18ft gates were fine for me.
Very top used T post insulators & post insulators, white flat elec. ribbon with solar charger. A driven ground plus I connected ground to fence.
I've never fenced but figured it out.