restore old chairs

[Pete112]

I'm looking for some guidance on restoring these chairs. It will be used for outdoors under covered patio. I was wondering what i need to do to restore these chairs? Couple questions I have are:

1. Do I need to sand this to bare wood, or can I apply a product on it without sanding?

2. What product should I use keeping in mind that it will be used outdoors in a covered area?

3. Can I change the colour, or is it best to try to stick to the colour it is now? It will be my first restore project