The training session is set to begin at 3 p.m.
Sharpen your discipline, whatever that might be. Could be kanji, could be baseball, could be curling. Whatever it is, when you sharpen it, you have to study. You have to do training. It's the only way to get better.
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.