Qíshì chuānzhe hòuzhòng de kǎijiǎ shàng le zhànchǎng.
The knight donned heavy armor and went to the battlefield.
Tips
memory
铠 (armor chest piece) + 甲 (shell / first / carapace) = protective shell. 甲 on its own can mean a hard shell (like a turtle's), so 铠甲 = the full armored shell that protects a warrior.
