I am using Windows 10 and I have attempted to download several extensions with Chrome and Edge browsers. With Chrome, I noticed their are 2 files downloaded in the browser. One says there is an error (see screenshot).

Although all the extensions I have downloaded (from chrome and edge) show in EM I cannot see them in WL or access them.

For instance, the last time I did this over 2 yrs ago the Performance Visualiser extension once installed by downloading it from the website showed up as extra tabs in the Strategy box.

What I am doing wrong here?

I have attached pics of my addins and providers already downloaded.

pics attached

Attached screenshots tell that you can install extensions. It does not seem to me that you're having any issue (so I've renamed the misleading topic title).

Assuming you've restarted Wealth-Lab Developer (which is required), to make a visualizer show up as extra tab please activate it (or them) in the Preferences dialog > Performance Visualizers first.

If you still have questions regarding the other extensions, fire away.