What is the best way to promote a newly established cannabis company in the eastern European country at the early stage of Legalization? Should we start with the social media campaign?

There are so many variables here. The biggest question is abotu local laws. Albania is different than Czech Republic, for example. If "early stage" still means "illegal" then the country where you are will be a very important determining factor. That said, my advice to any start up is to begin with branding and identity. Who are you and what do you look like? Then a website. And then social media.

PS: I spent a couple years in Prague after college and got to travel around a bit. I would be interested in learning more.