Do I need to install Flash player on my PC
OS: Windows 10 Pro 64-bit
CPU: AMD Ryzen 5 2600 3.4GHz Six-Core
RAM: 8.00GB 1330MHz
Motherboard: Gigabyte A320M-H-CF
Graphics: AMD Radeon RX 580 4GB GDDR5
Display: Samsung SyncMaster P2050 1600x900 60Hz
HDD: Hitachi HDS721010CLA332 1TB
SSD: KINGSTON SA400S37120G 120GB
Two questions for you
1. What web browser(s) do you use [some have it already]?
2. Have you had any messages telling you that you need Flash [most sites have stopped using it]?
And I also can't enter the Flash player download page at all
Ok, Chrome includes Flash Player "out of the box". No need to download it or install it. However, it is deliberately annoying to use, you have to enable it every single time. Google have said they will block Flash forever at the end of this year (and so will the other major browser makers).
By the way, watch out for FAKE sites which tell you need Flash Player and offer a download. Don't go there! Quick way to get a virus!!
Ok but do I need it installed on my computer for other programs and maybe games
Like I said, you already have it. You MUST already have it because you have Chrome. Do not try to download it. Instead, look into making it activated when you use it. https://support.google.com/chrome/answer/6258784?co=GENIE.Platform%3DDesktop&hl=en Some Flash sites won't work, and prepare for them all to stop working at the end of 2020.
I mean on Windows and other programs not Chrome
Do you have any specific Windows programs which say they need Chrome? You'd probably need to deal with their needs separately, it would be impossible to "install it in case they need it" for every case.