Replace link (#1319)

* fixed link

* updated link

* Update index.md

* corrected link

Author: catalinaadam

docs/index.md

@@ -27,7 +27,7 @@ A minimal PMM set-up comprises one [server](details/architecture.md#pmm-server)
 
 - An [easy install] script, which you download, make executable and run. The script installs Docker and runs PMM Server as a container.
 
-- The [Quickstart install guide] shows how to run PMM Server as a Docker container, and how to install PMM Client on Ubuntu or Red Hat Linux hosts.
+- The [Quickstart install guide](quickstart/index.md) shows how to run PMM Server as a Docker container, and how to install PMM Client on Ubuntu or Red Hat Linux hosts.
 
 - [Setting Up] explains in detail how to set up PMM Server, clients, and how to add services.
 
@@ -179,4 +179,3 @@ A minimal PMM set-up comprises one [server](details/architecture.md#pmm-server)
 [Technical Preview]: details/glossary.md#technical-preview
 [easy install]: setting-up/server/easy-install.md
 [Setting Up]: setting-up/index.md
-[Quickstart install guide]: https://www.percona.com/software/pmm/quickstart