It is a bit of work! Digging the post holes is not easy, I suggest hiring out.
If being used a a property divide, get the county surveyor out for proper placement.
It works the same as wood fencing. Setting the post in concrete, then attaching the fencing.
Spend the money on treated lumber posts if you don’t want wood rot & termites making them being replaced in 10 years.
Those posts have to go on your side of the property line, if putting it on the line (6” your direction).
Hi Gloria, here's a video showing vinyl being used as a gate. It will help you understand the process. Then there's other videos if you google "install vinyl fencing" in your menu bar. Hope this gets you started!