Canon Rebel questions

We have a t6i and we got it only a few weeks before we left to India and neither of us hardly know how to change the manual settings or what they’re for. We would like to figure out how to set up the camera for long exposure night shots and I’ve read and understood the basics but I want a link to an actually well put together explanation. Does anyone have recommendations for tutorials to watch or workshops to look into once I arrive stateside again?