Recently, In Front of This
Noun and の adjective
このまえ
そういえば、この前、しょうてんがいでさくら子ちゃんとバッタリ会ったよ。
That reminds me, last time I was at the shopping district I ran into Sakurako.
この前、日本ごの曲のCDを買ったんだよね。
I recently bought a Japanese music CD.
この前に赤色の花を置くのはどう？
What about putting red flowers in front of this?
この means "this", and you know what the word 前 means (front/before). The combination of these words, "this before" if you will, can mean a few different things. If we're talking about when something happened, the "before" meaning kicks in, and it means the other day or recently. If we're talking about location, then the "front" meaning kicks in, and it means in front of this.
The reading for 前 is the kun'yomi, like the reading for the vocabulary word 前. So long as you know that word, you'll be able to read this one too. The reason it's not on'yomi is because it's like two words put together. The word この and the word 前.