我曾经在厨师学校学习一个月。 In this sentence, "厨师学校"means a school which can teach you the professional skills of being a chef. But in China, we just call it "烹饪（pēng rèn）学校".^^

This sentence is past perfect tense “厨师”means the person who make meals. “厨师学校”means the school which teach you professional cooking skills

“厨师学校” means “cooking school” or “culinary school”. "厨师" means “chef”. We usually say "烹饪学校" or“烹调学校” instead of “厨师学校” in China. Obviouly, "厨师" is an adjective in THIS CONTEXT. It just omits the "的" in Chinese. It should be "厨师的学校". So some people might mistakenly consider the "厨师" HERE as a noun. 我曾经在厨师学校学习一个月. This sentence means that I once learnt in culinary school for a month. Hope this helps. :)))