Many years ago when I thought about this, I realised I wouldn’t be able to put much of my modern knowledge and skills to use. I decided I’d learn to make basic matches by distilling urine into phosphate, which wasn’t invented until the 19th century, but I’ve forgotten the process. Collect lots of urine and boil it? Also, if you make white phosphate it can cause horrific toothache and they have to remove your jaw… So, I’m hoping another commentor will suggest a safer skill I can brush up to be ready for travel.