Basic lifesaving skills...
It's kind of shame that in this day and age it may be necessary to use a tourniquet on yourself or your loved ones, but it can be a lifesaver (literally) if needed. When emergencies happen especially if it is a mass casualty event emergency medical response can easily become overwhelmed and you may be on your own for a significant amount of time. It only takes about 3 minutes for an adult human to bleed out if a major artery is injured.
I just found this app that has videos and materials built in that can provide a reference point and provide supplemental or refresher training, but could also serve as a solid start point if you are looking to learn.
The 2 recommended tourniquets are the North American Rescue CAT (Combat Application Tourniquet) and the Tactical Medical Solutions SOFTT-Wide.
If you have questions about tactical casualty care please reach out. I will try to help you myself or point you in the right direction!