Hello adivajra,
Congrats on upgrading! Once you get up and running I’m sure you’ll love it. 😀
First, it might be helpful to check out our primers. They’re quick videos that will bring you up to speed quickly.
The pro plugin is an add-on, you install and activate it along with the free The Events Calendar plugin you already are using. So you won’t lose any data at all!
Of course, this is a great opportunity to add: Always have a recent backup of your site! I’m assuming nothing bad will happen, but better to be safe than sorry.
Does this make sense? Let me know if I can explain anything else!
Cheers!
– Casey Driscoll