After SHTF there will be no time to learn the skills needed to help insure that you remain safe. Survival skills are something that can't be bought and stored, but instead needs to be stidued and will take practice. There are several venues to find information covering survival skills, so your best bet is just dive in and get your learn on.
To know what survival skills will be most beneficial for you to learn will depend on your own situation. There are several great informative channels on You Tube that will get you started, but you need to actually take the time to practice the skills as you learn them. Some skills will be just a matter of having the knowledge and then apply that knowledge when the time comes. But, you may want to practice other things like friction fires and shelter building because they do take a bit of practice to master.
It is important to study and practice survival skills before you need them. It will allow you to be more confident and focused instead of being panicked and disorganize when you're faced with a disaster. You will find yourself more level headed if you have a plan and a basic set of survival skills before you find yourself in a survival situation. Do not put this area of preparation off until the last. This area will more than likely be the one that ultimately saves your life. So, consider your possible scenarios that you might face and then make a list of survival skills that may come in handy in that particular situation.