Update data on Wix

I have read the page about wix-users, and I still don’t get it.
I have a website on wix where I want my clients to add their details into a DB called “members”, and update those details when they want.
So in theory, this input fields should be empty if the client have never filled this out, or showing the current details if the client has filled this before.

This is what is happening at the moment:
The same person has logged and filled the details 3 different times, and it is basically creating new items even though the person has already got an account on my website. Once they add their details, they are able to see that. After a while, their details just disappear from the page, but they are still in the live Data Base (but it is creating a different ID for the user).
Any way I can limit this so people only have one item (like the the user ID to see if this person already have details, and if yes, show them, and update them instead of creating a new row).

Any help appreciated!

You should add the stuff on the members page, add a new navigation item on that page. That page will be unique for each logged in use. Then make sure you use dataset and set condition to logged in user to your dataset and update / submit and set it to read / write not write, if you only have write it will create new items.

Hi Andreas, I had read/write before but sometimes the “submit” button and the field forms would just not work, so I changed it to “write” and they did, but then this happended.
I changed it back to read/write, and most of the pages are working properly now!
I will try to add the forms and buttons again for the ones that are not. Many thanks!