Honhonhon oui oui baguette!

Not too bad :-), but not perfect

Here is the corrections:

Quand ils apprendront que ce serveur est bilingue, cela va etre très amusant.

Futur tense because they are going to learn in the futur.

‘It’ in the second part refer to the previous sentence. It could be replaced by ‘that’ or ‘this’