OPKs help!!!

Janelle • Sat, Nov 01 • Baby #1 due November 2nd

Ok so I'm so confused here!! My clearblue advanced digital is saying I need to use my first morning urine and some of you guys on here said I need to take it in the afternoon?

So which is right? If it is in the afternoon then what time should I take it? I'm going to buy some internet cheapies to check those to.