fixed some moments in the RGF installation guide (#201)

* fixed some moments in RGF installation guide

* hotfix in Unix-like systems installation guide

RGF/README.md

@@ -125,16 +125,21 @@ Otherwise, your executable can be anywhere you like.
 
 ### 3.1.1. Precompiled File
 
-The easiest way. Just download the precompiled file `rgf.exe` from the latest [GitHub release](https://github.com/RGF-team/rgf/releases).
+The easiest way. Just download the precompiled file `rgf.exe`
+from the latest [GitHub release](https://github.com/RGF-team/rgf/releases).
 
 For 32-bit Windows download `rgf32.exe` file and rename it to `rgf.exe`.
 
 ### 3.1.2. Visual Studio (Using the Provided Solution File)
 
 1. Open directory `Windows/rgf`.
-2. Open `rgf.sln` file with Visual Studio and choose `BUILD -> Build Solution (Ctrl+Shift+B)`.
+2. Open `rgf.sln` file with Visual Studio.
 
-   If you are asked to upgrade the solution file after opening it, click `OK`.
+   If you are asked to upgrade the solution file, click `OK`.
+
+3. Choose `Release` from the **Solution Configurations** listbox
+   and `Win32` or `x64` depending on your machine architecture from the **Solution Platforms** listbox on the standard toolbar.
+4. Choose `BUILD -> Build Solution (Ctrl+Shift+B)`.
 
    If you have errors about **Platform Toolset**, go to `PROJECT -> Properties -> Configuration Properties -> General`
    and select the toolset installed on your machine.
@@ -145,6 +150,7 @@ Build executable file with MinGW g++ from existing `makefile`
 (you may want to customize this file for your environment).
 
 ```
+mkdir bin
 cd build
 mingw32-make
 ```
@@ -189,6 +195,7 @@ Build executable file with g++ from existing `makefile`
 (you may want to customize this file for your environment).
 
 ```
+mkdir bin
 cd build
 make
 ```