doc: more information on portfile

doc/source/markdown/installation.md

@@ -2,12 +2,17 @@
 
 ## using vcpkg
 
-Currently only installation using custom a GitHub repo port ist implemented: See for relevant files.
-You may need to update `SHA512` in [`portfile.cmake`](./port/portfile.cmake).
+Currently only installation using an [overlay port](https://learn.microsoft.com/en-us/vcpkg/concepts/overlay-ports) is
+implemented. Files can be found in `port/` or in releases.
 
 ### Tutorial for manifest mode
 
-1. Save files in [`port/`](./port) to your local disk, for example `<proj_root>/ports/`.
+1. Save files vcpkg files to your local disk, for example `<proj_root>/ports/`.
+    1. You may find them added to release tags
+    2. If your targeted release does not contain vcpkg file:
+        1. copy files from `port/`
+        2. update `REF` to your release tag and continue with steps 2-4.
+        3. Step 4 might crash because of a Hash-Mismatch, update `SHA512` to the hash vcpkg shows you
 2. register port dir for example by creating `<proj_root>/vcpkg-configuration.json`:
 
 ```json
@@ -40,5 +45,5 @@ find_package(ntfy-lib)
 target_link_libraries(<proj> PRIVATE ntfy-lib::ntfy)
 ```
 
-6. Follow [Examples](#examples)
+6. Follow [Examples](./examples.md)