Duck laying eggs in my garden

Every year one female and 2 male ducks come to our garden for a while. This time they disappeared after a while but the female has returned. She’s been on her own all day and has just laid one egg. I have a few questions and really hope someone can help

shes under a picnic bench covered in stuff, does the nest need to be waterproof? It currently isn’t 

she hasn’t built a nest, she’s just sat on some paving, is that okay? Do I need to give her some hay? Or something 

She has moved away from the one egg she laid. Shall I place it near where she is now? It’s just sat uncovered. 

would a shallow container of water help or will she be okay not swimming while she is nesting? 

once the ducklings hatch, to get to water she has to walk down one busy road then cross another road to get to water, would it be easier for me to carry the ducklings in a carrier? Or do I just pray I’m here and notice so I can follow her. 

we have lots of cats around here, anything I can do to help keep her safe?