Hi @Carol256
Welcome to Airbnb.
I had a look at your listing and thought you might appreciate a few comments to help you get started. Yes your room/s are available for the public but the price and lack of availability will limit those who look for it.
1. You do have a duplicate listing - contact Airbnb and ask them to remove it. (2nd post Community Help for contacts)
2. You have lots of dates blocked out in the forthcoming months, so Airbnb won't prioritise your listing in the rankings
3. 300 pounds a night for room in a shared place in Cardiff. Are you sure? - I could get a house for that or a five star hotel.
4. You say in your listing that your room is bright but in the photos it looks dark. You also mention the lovely view but have no photos of it.
I hope you don't mind me suggesting it, but I would go through the bedroom and bathroom with an eye to the design and strip out any clutter and mismatching items. Have netural matching bedside lamps, quality bedding with matching towels with co-ordinating curtains/blinds, bring colour to the room with say some quality photos of the harbourside. Strip the bathroom so you just have a decent matching, bath/shower gel, shampoo, soap and conditioner and perhaps some wall decorations. Any surplus items can go.
When you have done this request an Airbnb photographer or commission a local freelance.
Then review your pricing so it is more in line with comparable nearby properties.
Here are a few nearby to give you an idea of your competition and properties designed to appeal to the Airbnb market
https://www.airbnb.co.uk/rooms/10327879?location=Cardiff%2C%20United%20Kingdom&s=zIJ2uTQT
https://www.airbnb.co.uk/rooms/17362033?location=Cardiff%2C%20United%20Kingdom&s=uRYEbn8F
https://www.airbnb.co.uk/rooms/15985802?location=Cardiff%2C%20United%20Kingdom&s=uRYEbn8F
https://www.airbnb.co.uk/rooms/18623738?location=Cardiff%2C%20United%20Kingdom&s=zIJ2uTQT
Good luck with your hosting.