Learn Hardcore Indonesian: Kerajinan bambu dipajang di galeri. - Bamboo handicrafts are displayed in the gallery.

kerajinan means handicraft or craftwork. Although it might look like rajin (diligent) + -an, it's actually a standalone noun. It often appears with a material: kerajinan bambu (bamboo crafts), kerajinan kayu (woodcraft). If you add tangan (hand) after it—kerajinan tangan—you emphasize it is handmade.

Why doesn't kerajinan bambu have a plural marker or an article like "the" or "a"?

Indonesian nouns do not change form for singular or plural.
There are no definite or indefinite articles.
To show plurality use words like beberapa (some) or banyak (many).
To make it definite you can add itu or tersebut after the noun (e.g., kerajinan bambu tersebut).

What does dipajang mean, and how is it formed?

dipajang is the passive form of pajang (to display). It is formed by adding the prefix di- directly to the root verb: di- + pajang = dipajang (displayed or are displayed). Indonesian verbs do not change for tense; context or time words tell you if it's happening now or happened before.

How can I tell the difference between the prefix di- in dipajang and the preposition di in ?