Using the converters
To convert a DokuWiki site to Confluence, set the file name pattern to ".txt" and set "Attachment directory" to the media directory for your site (it's in the same folder as the data directory).
Page hierarchies
By default, DokuWiki page hierarchies are not moved to Confluence. In stead, pages are renamed according to the hierarchy structure. E.g., if a page foo has a child page foo/bar, the page in Confluence will be named "foo - bar" and it will be a top-level page. All links will be converted and will work, but the hierarchy is lost.
It is possible to convert pages while preserving the hierarchy, but in Confluence there can only be one page with a given name in a space. Thus, if you have start and foo/start in DokuWiki, the page name conflict will result in only one of the pages appearing in Confluence. Even worse: the contents of that page will immediately be overwritten with the contents of the other page.
If your site does not have any page name conflicts, you can enable hierarchy conversion by uncommenting a line in converter.docuwiki.properties so that it looks like this:
DokuWiki.0.hierarchy-builder=com.atlassian.uwc.hierarchies.BaseHierarchy
Note that you will not get any warnings or error messages if there are any page conflicts, so be sure to check the results thoroughly!