In this context, "begitu" means "like that" so "tidak begitu" means "not like that"
I'm not sure if 'tidak' here is negating the adverb 'begitu' (tidak begitu = unlike that) or the implicit copulative (tidak = are not).
Also, how do I say "Can you say ...?" in Indonesian? What is the most natural way to say it? I need some basic classroom language. Thanks!