How install Plugins from Wed?

Hello friends, I can’t update plugins in Help->Update… I find many plugins can be installed in this wed -https://sites.imagej.net/, however , I need to load what in my computer and how to run them, just put those in plugins? Becaues i find many files in every plugin.屏幕截图 2021-01-23 222058

This documentation page explains how to activate an update site: