Have you looked at any inspiration pictures, how much seating would be ideal and based on room’s size (?) and what shape would you prefer.

Don’t purchase island seating until dining room is decided on. Did you want stools or backs and is functionality important (ie: young children).

For more helpful advice, can you show your living room so as to get a better sense of your style, provide as much info as you can and the budgets for both if you want actual links to suggestions.