Thickbox as frontpage

Is it possible to have a thickbox with a small explanation/introduction to my site pop up on the first load of my site with my normal blog page behind it?

I see that it’s possible to have a thickbox pop up with every load of a page but is it possible to have it just load on my main page and only on the first load?

Ideally i’d like a plugin as I have virtually no coding expertise at all!

Any help would be appreciated,
Stoned Hippy
https://www.itsalongwaytotipperary.net