Update README.md (#19457)

* Update README.md

Minor grammar and format edits

* Update README.md

packages/README.md

-## Grafana frontend packages
+# Grafana frontend packages
+
+This document contains information about Grafana frontend package versioning and releases.
 
 ## Versioning
-We use [Lerna](https://github.com/lerna/lerna) for packages versioning and releases
+We use [Lerna](https://github.com/lerna/lerna) for packages versioning and releases.
 
 All packages are versioned according to the current Grafana version:
 - Grafana v6.3.0-alpha1 -> @grafana/* packages @ 6.3.0-alpha.1
 - Grafana v6.2.5 -> @grafana/* packages @ 6.2.5
 - Grafana - master branch version (based on package.json, i.e. 6.4.0-pre) -> @grafana/* packages @ 6.4.0-pre-<COMMIT-SHA> (see details below about packages publishing channels)
 
-> Please note that @grafana/toolkit, @grafana/ui, @grafana/data & @grafana/runtime packages are considered ALPHA even though they are not released as alpha versions
+> Please note that @grafana/toolkit, @grafana/ui, @grafana/data, and @grafana/runtime packages are considered ALPHA even though they are not released as alpha versions.
 
 ### Stable releases
 > **Even though packages are released under a stable version, they are considered ALPHA until further notice!**
 
-Stable releases are published under `latest` tag on npm.
+Stable releases are published under the `latest` tag on npm.
 
 ### Alpha and beta releases
-Alpha and beta releases are published under `next` tag on npm.
+Alpha and beta releases are published under the `next` tag on npm.
 
-### Automatic pre-releases
-Every commit to master that has changes within `packages` directory is a subject of npm packages release.
-*ALL* packages will be released under version from lerna.json file with commit SHA added to it:
+### Automatic prereleases
+Every commit to master that has changes within the `packages` directory is a subject of npm packages release. *ALL* packages must be released under version from lerna.json file with commit SHA added to it:
 
 ```
 <lerna.json version>-<COMMIT_SHA>
 ```
 
-Automatic prereleases are published under `canary` dist tag.
+Automatic prereleases are published under the `canary` dist tag.
 
 ### Manual release
-> **Checkout** to the tag you are about to release first, i.e. `git checkout v6.4.0`
-
-> Make sure **you are logged in to npm** in your terminal and that **you are a part of Grafana org on npm**
 
-In Grafana's repo main directory **run**:
+> All of the steps below must be performed on a release branch, according to Grafana Release Guide.
 
-```
-./scripts/build/release-packages.sh <VERSION>
-```
+> Make sure you are logged in to npm in your terminal and that you are a part of Grafana org on npm.
 
-where `<VERSION>` is the same as the version tag, i.e. `v6.4.0`
+1. Run `yarn packages:prepare` script from the root directory. This performs tests on the packages and prompts for the version of the packages. The version should be the same as the one being released.
+   - Make sure you use semver convention. So, *place a dot between prerelease id and prerelease number*, i.e. 6.3.0-alpha.1
+   - Make sure you confirm the version bump when prompted!
+2. Commit changes (lerna.json and package.json files) - *"Packages version update: \<VERSION\>"*
+3. Run `yarn packages:build` script that prepares distribution packages in `packages/grafana-*/dist`. These directories are going to be published to npm.
+4. Depending whether or not it's a prerelease:
+   - When releasing a prerelease run `packages:publishNext` to publish new versions.
+   - When releasing a stable version run `packages:publishLatest` to publish new versions.
 
+5. Push version commit to the release branch.
 
 ### Building individual packages
-To build induvidual packages run `grafana-toolkit package:build --scope=<ui|toolkit|runtime|data>`
-
+To build individual packages, run: 
 
+```
+grafana-toolkit package:build --scope=<ui|toolkit|runtime|data>
+```