JoomSuite Inbox is an add-on component of Joomla. Therefore, to install JoomSuite Inbox, ensure that Joomla is already installed and FTP is enabled as well. Also, ensure that the following softwares are installed on your machine/server where you want to install Joomla:
To install JoomSuite Inbox:
1. Log into http://joomsuite.com.
In order to log into the above mentioned website, you should be registered to joomsuite.com. After you register, you are automatically logged into the website.
2. Navigate to Downloads-> JoomSuite Downloads.
3. Scroll down the Web page that is displayed after clicking JoomSuite Downloads, and click the JoomSuite Inbox link  under the Category Index section, as shown in the following figure:
4. Scroll down the Web page that is displayed after clicking the JoomSuite Inbox link, and click the JoomSuite Inbox 1.0.1 Beta 1 (PHP5) link , as shown in the following figure:
5. Scroll down the Web page that is displayed after clicking the JoomSuite Inbox 1.0.1 Beta 1 (PHP5) link. Click the com_jsinbox.1.0.1(php5).zip link , as shown in the following figure and download the JoomSuite Inbox software:
6. Visit http:/localhost/Joomla/administrator. Enter valid credentials and log into Joomla back-end.
7. Navigate to Extensions-> Install/Uninstall. In the Package File text box , enter the path of the JoomSuite Inbox software, which you have downloaded in step 5 or click the Browse button  to locate the JoomSuite Inbox software. Click the Upload File & Install button  shown in the following figure:
Congratulation!! You have successfully installed JoomSuite Inbox.