What @Matilda1981 described seems like the usual course of events. I think people do expect something , if you just scatter the ashes it will be over in 30 seconds and you will be looking around at each other wondering what to do next .
So you do want some structure or plan, however simple.
It’s nice to have a few words spoken to remember the person , perhaps a song played or poem read that was special or them or that reminds you of them. Ideally something that celebrates their life, rather than talking about their death.
Some people lay some simple flowers ( not a wreath ) or even one bloom , like a rose.
If you are religious , often people say a prayer together or one person reads a prayer or special verse from a religious text. A quiet moment of personal reflection is alway good.
And then going somewhere for something to eat / drink together. you want to end the day / event feeling that you have happy memories of someone you loved. And you have shared these moments with others who loved them too.
These rituals are important in our grief . It won’t be fun but you want to feel at the end of the day that you are glad you did it and your loved one would have been proud of how well you are all coping.