diff --git a/README.md b/README.md
index 68f05a9..10fb277 100644
--- a/README.md
+++ b/README.md
@@ -6,6 +6,7 @@ chkusr is a set of programs to verify information about a user on UNIX based sys
 
  * [The idea](#the-idea)
     * [Requirements](#requirements)
+    * [Configuration](#configuration)
     * [Building chkusr](#building-chkusr)
     * [Installation](#installation)
     * [Uninstall](#uninstall)
@@ -25,13 +26,15 @@ chkusr is a set of programs to verify information about a user on UNIX based sys
 
 ## The idea
 
-I needed some programs to verify some information about users and groups on a Linux/UNIX system just returning 0 on success and 1 on error.
-
-Currently chkpwd is only tested on Linux, but it should work on a [AIX](https://en.wikipedia.org/wiki/IBM_AIX), [DragonFly BSD](https://www.dragonflybsd.org/), [FreeBSD](https://www.freebsd.org/), [HP-UX](https://en.wikipedia.org/wiki/HP-UX), [Linux](https://kernel.org/), [macOS](https://en.wikipedia.org/wiki/MacOS), [NetBSD](https://netbsd.org/) and [Solaris](https://en.wikipedia.org/wiki/Oracle_Solaris) operating system too.
+I needed some programs to verify some information about users and groups on a Linux/UNIX system just returning 0 on success and 1 on error. Some programs also return a message.
 
 ### Requirements
 
-You need the PAM development package installed. On Alpine it is named linux-pam-dev, on Debian based systems it is libpam0g-dev.
+You need the PAM development package installed. On Alpine it is named linux-pam-dev, on Debian based systems it is named libpam0g-dev.
+
+### Configuration
+
+chkusr needs to be configured before compilation. Always look at config.h for configuration options. I did it this way because I need the programs as small and simple as possible, and I don't want to parse a configuration file.
 
 ### Building chkusr
 
@@ -59,19 +62,23 @@ chkpwd.h is installed to /usr/include/ for use in other applications.
 sudo make uninstall
 ```
 
-## chkgrp
+## Programs
+
+### chkgrp
 
 chkgrp is a program to verify if a user is a member of a group.
 
 More information will follow... Actually there are multiple programs with some different behavior. I will write more about this, but for now I will not.
 
-## chkpwd
+### chkpwd
 
 chkpwd is a program that checks the validity of a users password on a UNIX/[PAM](https://en.wikipedia.org/wiki/Pluggable_Authentication_Module)-based system.
 
+Currently chkpwd is only tested on Linux, but it should work on a [AIX](https://en.wikipedia.org/wiki/IBM_AIX), [DragonFly BSD](https://www.dragonflybsd.org/), [FreeBSD](https://www.freebsd.org/), [HP-UX](https://en.wikipedia.org/wiki/HP-UX), [Linux](https://kernel.org/), [macOS](https://en.wikipedia.org/wiki/MacOS), [NetBSD](https://netbsd.org/) and [Solaris](https://en.wikipedia.org/wiki/Oracle_Solaris) operating system too.
+
 The code only supports verifying passwords for user id 1000 by default. Look at the file chkpwd.h for some compile time options!
 
-### Usage
+#### Usage
 
 ```
 chkpwd -h
@@ -91,37 +98,37 @@ You can also use chkpwd even without installing by just running the following co
 ./chkpwd
 ```
 
-#### Return codes
+##### Return codes
 
 chk returns 0 on success, 1 otherwise.
 
-#### Examples
+##### Examples
 
-##### Interactive mode asking for a username and a password
+###### Interactive mode asking for a username and a password
 
 ```
 chkpwd
 ```
 
-##### Interactive mode only asking for a password
+###### Interactive mode only asking for a password
 
 ```
 chkpwd -u hanez
 ```
 
-##### None interactive mode with username and password provided as arguments to chkpwd
+###### None interactive mode with username and password provided as arguments to chkpwd
 
 ```
 chkpwd -u hanez -p password
 ```
 
-##### Request the result from the above commands
+###### Request the result from the above commands
 
 ```
 echo $?
 ```
 
-#### Custom build
+##### Custom build
 
 Set MAX_UID and MIN_UID at compile time:
 
@@ -129,7 +136,7 @@ Set MAX_UID and MIN_UID at compile time:
 gcc -Wall -DMAX_UID=1000 -DMIN_UID=1000 -o chkpwd chkpwd.c -lpam -lpam_misc
 ```
 
-## chkpwr
+### chkpwr
 
 A program to validate a string with a password rule. More to come...