Original Poster: Linuxera
Installation and Use of the Lightning Plug-in with Thunderbird
This is one of the handiest gadgets that Mozilla has offered, and just a few clicks away.
First click on Tools > Addons
in the lower right hand corner click on Get Extensions, which will take you right to the Mozilla Site. Type Lightning in the search field and the plug-in will appear. Download to where you like downloading files (I downloaded to the desktop for easy reference). Once the download is completed, click on the 'Install' button of the Add-ons window and navigate to the desktop. Click on the Lightning package you've just downloaded and Thunderbird will do the rest.
Restart Thunderbird, and now on the lower left panel you will see 3 icons. If you want to read email, click on that icon, If you are wanting to see the calendar, then just click on that icon, etc.
The Calendar layout is very similar to Outlook. You can change from a single day to week or month layout using the icons at the top of the window. Everything is pretty much self explanatory.
To add an event to the calendar just double-click on any day or time slot and and a new window will pop up allowing you to name the event, and adjust time, duration, location and importance.
Another nice feature of the Lightning plug-in is the right side bar. Using the cursor you can hide or show it, just as you can the left side bar. Adding tasks is as easy as adding an event to the calendar. Just click on tasks in the lower left panel, and the tasks panel will appear in the center. Type in your task in the box above and use the icons on the top frame to identify Category, etc.