Did you create the custom table with code? The MB Custom Table doesn’t create the table automatically. Instead, you need to put a small snippet into your theme’s
functions.php file to create a table manually. Here is the guide on doing that.
If you already did that but no tables are created, please check if your database user has privileges to create new tables. Some hosts don’t allow you to do that.
Regarding issue with displaying fields on the front end, are the fields just normal custom fields or they’re fields used with custom table? As there is still a problem with custom table, the custom fields don’t work properly until we resolve it.
I’ll answer your question about MB Relationships in another topic of yours.