Always hire license contractors to do your job by state law they have to be insured and bonded.
Not sure where your property line is get a survey.
Make sure your post can drain properly when there installed. Post will start to rot very fast when post can’t drain water out bottom.
Proper nails are used to install your treated lumber.
Seal fence as soon as possible the more time it has to get wet and dry out the higher your risk of bowing , shrinking and cracking.
Cedar will not shrink like pine.
Fences and decks are not recamended to be installed when it’s raining or weather is bad.