Beforehand, In Advance, Previously, Ahead Of Time
adverb
The kanji and the word are almost exactly the same. That means they share meanings as well.
あらかじめ
Since this word consists of a kanji with hiragana attached, you can bet that it will use the kun'yomi reading. You didn't learn that reading with this kanji, so here's a mnemonic to help you: What did you do beforehand? You had a raw casual (あらかじ) encounter with a raw Cage, Nic Cage. You probably should have planned something better ahead of time.
こうなることは分かっていたので、予め用意しておきました。
I knew it would happen, so I prepared ahead of time.
予めフライト前日にオンラインでチェックインしておきました。
I checked in online on the day before the flight.
予め予習しておいた甲斐がありました。
Preparing the lesson in advance was worthwhile.