Titration is the process of determining the true, real, or minimally effective, dose, value, content....etc. While you are asleep, and after noting several rounds of obstructive apnea and hypopnea (low breathing flow) [and not 'hypoxia', although they tend to run hand-in-hand], the tech will commence flow via a CPAP machine and he/she will increase and decrease values, both during inspiration and expiration. The body often relaxes and sleeps better not fighting a constant flow such as that needed to splint your airway during intake. So, there is a setting for EPR (expiration pressure reduction) where the machine senses that you have finished inhaling and it backs off the flow to let you exhale more naturally. It's a comfort feature, but comfort is really important with all the other intrusiveness and changes you'll have to adapt to over the next few weeks.
Your best ally in all of this novelty is your own attitude. If you want this to work, if you're determined to learn lots, and you are hell-bent to succeed and not be defeated or afraid, you'll succeed.