Halo teman! The plural for things would be "itu" or "ini". Example:

Those apples are delicious. Gather them here. / Apel-apel itu enak. Kumpulkan itu di sini.

Breaking it down:
Those (itu) apples (apel-apel / apel) are (pause / zero copula) delicious (enak)
Gather (kumpulkan) them (itu / ini) di sini (here)

Even, I have seen some mistakes before in the course for Indonesian speakers, those have been fixed. Also, maybe some native speakers could mix "itu" with "mereka" in colloquial speech.

I hope it helps.

Selamat belajar! :)