the correct way to Sunction

Lippincott's Manual of Nursing Practice has a great description of this procedure. There is absolutely considerable skill involved.

Make sure you pre-oxygenate for at least 3 breaths.

You have a clean hand and a sterile hand. The sterile hand has the suction catheter.

A patient needs to be suctioned if they're coughing, rattling, dropping their oxygen sats, tells you they feel like they're not able to breathe, or isn't doing well and you can't figure out why.

You go down until you elicit a cough or you're getting good return of secretions to let you know you're removing what you intended to remove.

If you're unsure about how to do this, find an experienced nurse to help you with your technique. If there aren't any you're comfortable with on your unit, ask your nurse manager to help you arrange some time in the ICU or another unit to work on this or any other skill you feel you need improvement on.

if im not mistaken, you should suction while withdrawing the cather and should be less than 15 secs and preoxygenate prior to it. suction them if they have secretions, lets say when you hear crackles.

NT suctioning definitely requires skill! Performing it incorrectly or unnecessarily can cause considerable harm and distress to your patient. Please read up on the technique or ask your facility's respiratory department to help you.