update readme

Author: alexcoder04

README.md

@@ -2,11 +2,14 @@
 # gomail
 
 One day my friend asked me if it's possible to automate sending e-mails, so I
-decided it's a great opportunity to practise Go and here it is - a tiny program
+decided it's a great opportunity to practice Go and here it is - a tiny program
 that can send e-mails via SMTP.
 
 **It was created for educational purposes only, don't use it to spread spam.**
 
+**You need to have an account on a mail server (e. g. Gmail, Outlook or own
+server) to use this program!**
+
 ## How to install
 
 ### Stable release
@@ -19,7 +22,7 @@ https://github.com/alexcoder04/gomail/releases/latest.
 ```sh
 git clone https://github.com/alexcoder04/gomail
 cd gomail
-make linux # or make windows
+make linux # or `make windows`
 ```
 
 ## How to use (important!)
@@ -30,32 +33,38 @@ executable is run in. Those are:
 
 ### `settings.yml`
 
+You can use another file by passing the `-s` flag (e. g. `gomail -s mysettings.txt`)
+
 The host address can vary depending on your e-mail provider, most likely it's
-something like *mail.domain.tld* or *smtp.domain.tld*. The port also is
+something like *mail.domain.tld* or *smtp.domain.tld*. The port is also
 different for different e-mail providers.
 
 For my provider, the username is the part of the address before the @-sign,
-but it may be the full address or something completely different for your
-e-mail provider.
+but it may be the full address (e. g. on Gmail) or something completely
+different for your e-mail provider.
 
 ```yml
 From: [email protected]
 Addr: smtp.example.com:587
 Host: smtp.example.com
-Subject: Hello friends!
 Username: [email protected]
 Password: YourSecureP4ssw0rd
+Subject: Hello friends!
 ```
 
 ### `recipients.txt`
 
+You can use another file by passing the `-r` flag (e. g. `gomail -r friendslist.txt`)
+
 ```text
 [email protected]
 [email protected]
 ```
 
 ### `mail.txt`
 
+You can use another file by passing the `-b` flag (e. g. `gomail -b hello.txt`)
+
 ```text
 Hello friends,