The steps are very simple. First, examine your conscience to try to remember all of the sins committed since your last confession. Some people find writing them down helps them recall the sins while in the confessional.
Next, go to confession and confess them! Don’t stop with simply remembering; go do something about it. Remember that if you truly forget a sin, that’s ok, it’s still forgiven, but that’s not an excuse to “forget” to bring up sins you’re embarrassed about. The priest won’t know, but you certainly won’t fool God or yourself. If you do remember something you forgot; it’s a great practice to resolve to confess it next time. It may already be forgiven; but it really helps the healing process to confess it anyway.
Finally, be truly sorry for the sins you have committed. The Church calls this many things “contrite” and “repentant” are terms often used but they all mean “sorry”. This includes a “firm resolve” to not commit the sins again.
That’s it! That’s all you need to do. Forgiveness is a free gift offered by Jesus Christ; all you must do is confess your sins and be truly sorry for them.