Get involved page should link to RC download or documentation

[come-nc]

https://nextcloud.com/contribute/ suggests «Testing upcoming Nextcloud Server releases is the best way of making sure the new release can do what you need it to do.», but gives no link or explanation about how to do so.

It should link to https://nextcloud.com/release-channels/ or https://nextcloud.com/install/ «Get involved» section.

Also, https://nextcloud.com/release-channels/ links to https://nextcloud.com/install/#testing-development , but there is no testing-development anchor on this page and the get involved section is a bit hard to find.