Recipient - the email address that will be getting pictures sent to it.
smtp server, port, username, password - this is info specific to your email account, usually available from your ISP or by looking in your mail programs account settings. smtp is the mail server you use(like smtp.ispname.com), port is the port it communicates on(usually 25 for smtp) and if your email account requires authentication then you have to fill in the name and password(or leave blank for none)
sender email- this is just the email address that the email appears to come from, you can probably put the same address here or create an email address just for your camera and put it here..... it's not that important but the email sent needs to come from someone.
SSL/TLS - this is for secure communication and is specific to your email account also, some servers let use use this and some don't.... again check your mail providers required settings.
Edit: for example if you use gmail, these settings work for me
recipient: myemail@gmail.com
smtp server: smtp.googlemail.com
port: 465
username: myemail@gmail.com
password: ***********
sender: myemail@gmail.com
use ssl--tls: SSL-TLS
Hope this helps a little, it's all to do with your mail provider and nothing to do with your dlink account.