Hello... that's not very clear:
This is the message on the right:
The Wordpress db tables that you try to import from need to be in the same database as the joomla tables! Otherwise the import is not going to work!
When you import the categories from Wordpress we will keep the same category-> child relationship that they had. The post from Wordpress will be also associated with the same category as in Wordpress.
In Wordpress you are able to assign several categories to one post. Joomla articles can have just one category, that is why when we import the post from Wordpress we just take the first assigned Wordpress category.
You can use \Clean migration\ option to delete all of your previous data from your database. This function will delete all of your old articles*, categories*, users* and tags*!
* Depends on your migration selection. For an example, if you don't select categories for migration, categories won't be deleted.
I didn't have any option not to delete the current data. What it says is not exactly that ALL THE CONTENT WILL BE DELETED.
so, the question is: I now have another blog I want to insert into a bigger joomla site. I don't want again the same to happen... is it possible to migrate to a category without erasing current content?