"Scream loudly, so we can hear you."
Translation:Teriak yang keras, agar kami bisa mendengar kalian.
Grammatically speaking, you should use "yang" instead of "dengan" in this particular sentence because it's in an imperative mood.
Kalian sudah teriak dengan keras agar kami bisa mendengar kalian. (You screamed loudly, so we could hear you.)
Teriak yang keras agar kami bisa mendengar kalian! (Scream loudly so that we can hear you!)
My explanation is based on a grammar textbook and an additional review by an Indonesian native language teacher talking about "yang" as an identifier of adverbs (source). The same pattern is applied to the following sentences:
"Adi belajar dengan rajin." (Adi studies hard.) ==> "Belajar yang rajin!" (Study hard!)
"Dia berpikir dalam-dalam." (He is thinking deeply.) ==> "Pikir yang dalam!" (Think deeply!)
This "dengan-yang" conversion is only for imperative sentences.
"Teriak" is actually both a noun and a verb. "Berteriak" is also a verb (probably preferred; see KBBI), but in an imperative sentence, you need to use the root word (i.e. you should drop "me-" or "ber-" prefix). For more information, please review the tips for Command skill.