DBT takes at least a year to learn all the skills and start to use them be default. Until then is ut helpful to practice a few that you feel will be most helpful when you are struggling.
The trick is to practice them on a daily/weekly basis when you are not freaking out. Practicing regularly will build up habits that will eventually kick in when you really need them.
Also, I'm not sure if you are in a formal class but usually the leader wants you to call, text, or email when you are in need of support. It is their job to walk you through it and remind you which skills to use.