[Docs] clarity in docs (#1392)

* clarity in docs

---------

Signed-off-by: luarss <[email protected]>
Signed-off-by: Vitor Bandeira <[email protected]>
Co-authored-by: Vitor Bandeira <[email protected]>

Author: luarss

docs/index.md

@@ -45,6 +45,33 @@ See these [tips](user/FAQS.md#how-do-i-get-better-search-results) to help improv
 
 ### Setup
 
+#### Supported Operating Systems
+
+Note that depending on the installation method, we have varying levels of 
+support for various operating systems. 
+
+Legend:
+- `Y` for supported.
+- `-` for unsupported.
+
+| Operating System | Local Installation | Prebuilt Binaries | Docker Installation | Windows Subsystem for Linux | 
+| --- | --- | --- | --- | --- |
+| Ubuntu 20.04 | `Y` | `Y` | `Y` | `-` |  
+| Ubuntu 22.04 | `Y` | `Y` | `Y` | `-` |
+| CentOS 7     | `Y` | `-` | `Y` | `-` |
+| CentOS 8     | `Y` | `-` | `Y` | `-` |
+| Debian 10    | `Y` | `Y` | `Y` | `-` |
+| Debian 11    | `Y` | `Y` | `Y` | `-` |
+| RHEL         | `Y` | `-` | `Y` | `-` |
+| Windows 10 and above | `-` | `-` | `Y` | `Y` |
+| macOS        | `Y*` | `-` | `Y` | `-` |
+
+```{warning}
+For macOS, local compilation for the modules `par` and `mpl2` are not
+fully supported due to an upstream issue with `or-tools`. We recommend
+Docker installation wherever possible.
+```
+
 #### System Requirements
 
 To build the binaries and run `gcd` through the flow:

docs/toc.yml

@@ -5,16 +5,16 @@ entries:
   title: User Guide
   entries:
   - file: user/BuildWithDocker
-    title: Build With Docker
+    title: Build Using Docker
     entries:
     - file: user/DockerShell.md
       title: Docker Shell utility
   - file: user/BuildWithPrebuilt.md
-    title: Build With Pre-built Binaries
+    title: Build Using Pre-built Binaries
   - file: user/BuildLocally.md
     title: Build Locally
   - file: user/BuildWithWSL.md
-    title: Build With WSL
+    title: Build Using WSL
   - file: user/FlowVariables.md
     title: Flow Variables
   - file: contrib/Metrics.md

docs/user/BuildWithDocker.md

@@ -19,20 +19,48 @@ then is recommended that you restrict the number of CPUs used by the scripts
 docker run --rm ubuntu:22.04 nproc
 ```
 
-You can restrict the number of CPUs with the `-t|--threads N` argument:
+### Build Using Docker from pre-built binaries
 
-``` shell
-./build_openroad.sh --threads N
+Courtesy of [Precision Innovations](https://precisioninno.com/), 
+they release `.deb` installers of OpenROAD for Ubuntu
+and Debian on a regular basis. 
+This greatly helps to reduce the compilation time needed. 
+
+We recommend to use a Docker image of a supported OS
+and install OpenROAD using the prebuilt binaries from
+Precision Innovations. 
+You can start the container in an interactive mode using 
+the command below. 
+
+```shell
+docker run -it ubuntu:22.04
 ```
 
-## Clone and Build
+Now you are ready to install the prebuilt binaries. 
+Please refer to the instructions for installing prebuilt binaries 
+[here](./BuildWithPrebuilt.md).
+
+### Build Using Docker from sources
+
+Alternatively, if you would like the latest commits from the OpenROAD repositories,
+do follow the instructions below. 
+
+
+#### Clone and Build
 
 The following instructions build the docker image with CentOS 7 as the base OS:
 
+
 ``` shell
 git clone --recursive https://github.com/The-OpenROAD-Project/OpenROAD-flow-scripts
 cd OpenROAD-flow-scripts
-./build_openroad.sh
+./build_openroad.sh 
+```
+
+You can restrict the number of CPUs with the `-t|--threads N` argument:
+
+``` shell
+./build_openroad.sh --threads N
 ```
 
 ## Verify Installation

docs/user/UserGuide.md

@@ -4,7 +4,7 @@ The OpenROAD Project uses three tools to perform automated RTL-to-GDS layout gen
 
 1.  [yosys](https://github.com/The-OpenROAD-Project/yosys): Logic
     Synthesis
-2.  [OpenROAD App](https://github.com/The-OpenROAD-Project/OpenROAD):
+2.  [OpenROAD](https://github.com/The-OpenROAD-Project/OpenROAD):
     Floorplanning through Detailed Routing
 3.  [KLayout](https://www.klayout.de/): GDS merge, DRC and LVS (public
     PDKs)