My nan died last week. I'm really not good with these things but do I send a sympathy card to my aunties? Do I also send one for my dad? Do I just text my aunties to say I'm sorry? What would you do?

A sympathy card is totally enough.
When my nan died my mom was sent a lot of flowers and as much as she appreciated them, she was really sad when they all died and she had to get rid of them. Might sound silly but it just reminded her of her loss.

I'm sorry for your loss, these things can be hard to navigate.
I agree with Leigh, flowers are nice but necessary. A card is enough or a text if you think they won't mind something less formal and you are attending the funeral.
When we have had family funerals, flowers haven't generally been sent to us individually but sometimes people have wanted to send flowers via the funeral director to be used during the funeral. Of course we appreciate any flowers sent that way but have also asked if people would rather donate to a relevant charity instead of spending on flowers. We've always donated the funeral flowers to a local nursing home afterwards too.

Thank you. I've sent cards off. And will buy flowers for the funeral 💛