If you have seed, scatter and cover lightly with soil. If you have roots / tubers, pop them in the soil an inch or so down. They must have a sunny spot for the flowers to open. They're also known as 4 o'clock plants as the flowers open in the afternoon and are supposed to stay open all night, but I haven't checked on this. I had some many years ago from a Turkish Cypriot lady who childminded my youngest sprog. She grew them as they reminded her of "my country" :-)