Dia belajar keras setahun untuk lulus peperiksaan biasiswa.

Keras is an adverb here meaning “hard” or “intensely.” In Malay, adverbs often follow the verb:

• belajar = to study
• belajar keras = to study hard

This is similar to kerja keras (“work hard”).

• setahun literally means “one year.” The prefix se- replaces satu (one).
• satu tahun also means “one year,” but is slightly more emphatic.
• selama setahun means “for a duration of one year,” with selama indicating the entire span of that period.

In this sentence, setahun implies “for a year” without needing selama because context (duration of study) is clear.

Untuk introduces a purpose, similar to “in order to.”

• untuk lulus = “in order to pass”

You can also say supaya lulus or agar lulus, but these are more formal and sometimes require a subject:

• supaya dia lulus
• agar dia lulus

With untuk, you generally omit the repeated subject, making the sentence more concise.

This is a compound noun meaning “scholarship exam.”

• peperiksaan = exam
• biasiswa = scholarship

In Malay, descriptive nouns follow the main noun, so peperiksaan biasiswa literally reads “exam of scholarship.”

Malay allows you to omit the subject in a subordinate clause if it’s the same as the main clause’s subject. Since dia is already the subject of belajar, you don’t need to say dia lulus again. You could add it for clarity or emphasis:

• Dia belajar keras setahun untuk dia lulus peperiksaan biasiswa.
  But this is redundant in everyday speech.