What sort of advice?
If it is care, then you will need more than one, (they get lonely otherwise and do what they can to escape!) good fencing, a shelter, to get out of the rain particularly, a regular farrier to keep hooves trimmed and neat....and definitely no lush grass.
Donkeys are very long lived, and can be real characters. Good luck with them, and if you do get some....don't forget we need pictures.