Transfer the water to a small pot, add sugar and lemon juice and bring it to a boiling again. Cook for around 10 minutes until it reaches a wanted thickness.
Then turn off the fire, let it cool down a little bit and add the flowers removed in the previous step (recommend only half the flowers). This is mainly for decorative purpose.
Your homemade osmanthus syrup is now ready to use in various recipes, including the osmanthus oolong tea with coconut milk and crystal boba! Enjoy!