Add reddit badge, Update "how to build" to mention the scripts.

README.md

@@ -1,5 +1,5 @@
 
-[![you can get this shield at shields.io](https://img.shields.io/discord/771316156203270154?color=7289da&logo=discord&logoColor=white)](https://github.com/supermerill/SuperSlicer/issues/611#issuecomment-907833287)
+[![you can get this shield at shields.io](https://img.shields.io/discord/771316156203270154?color=7289da&logo=discord&logoColor=white)](https://github.com/supermerill/SuperSlicer/issues/611#issuecomment-907833287) [![you can get this shield at shields.io](https://img.shields.io/reddit/subreddit-subscribers/slic3r)](https://reddit.com/r/slic3r) 
 # SuperSlicer
 
 **A PrusaSlicer fork (which is a slic3r fork)** (previously Slic3r++)

doc/How to build - Linux et al.md

@@ -34,6 +34,12 @@ git submodule update
 
 ## How to build, the easy way
 
+After cloning, execute `sudo ./BuildLinux.sh -u`
+And then `./BuildLinux.sh -dsi`
+The compiled executable should be in the build/package folder
+
+## How to build, the guided way
+
 You can follow the [script](https://github.com/supermerill/Slic3r/blob/master/.github/workflows/ccpp_ubuntu.yml) the build server use to create the ubuntu release.
 
 You have to execute each command at the right of the 'run: ' tags, in the directory that is at the right of the previous 'working-directory:' tag.

doc/How to build - Mac OS.md

@@ -24,6 +24,12 @@ and then you have to clone the profiles submodules
 cd resources/profiles
 git submodule update
 ```
+
+## How to build, the easy way
+
+After cloning, execute `./BuildMacOS.sh -i`
+The executable & dmg should be somewhere in the build directory. 
+
 ### How to build
 
 You can follow the [script](https://github.com/supermerill/Slic3r/blob/master/.github/workflows/ccpp_mac.yml) the build server use to create the ubuntu release.