To insert your menstrual cup you will need to fold it first. Most people will find that the Punchdown Fold or the C-Fold methods are all they need, these two folds are both simple and quick to perform.
If those folds don't work for you there are quite a few other styles you can try. The trick is to test out different folds and also try various positions (leg up on the toilet seat, squatting, etc) in combination with angling your cup in different ways. This trifecta will ultimately lead you to getting your cup into the right place and a leak free experience.
To learn each menstrual cup fold you can find them all outlined in this comprehensive post on Period Nirvana. There are photo guides, a video, and gifs.
If you need more help with your menstrual cup reach out to orders @ period.shop with your question. We'd love to help you find and/or succeed with your menstrual cup.