Well, after reading that link more carefully,
I think that guy is suggesting you convert some table values to values that are compatible with WordPress by using this SQL script:
SELECT storyid AS ID, 1 AS post_author, FROM_UNIXTIME( published ) AS post_date, FROM_UNIXTIME( published +43200 ) AS post_date_gmt, bodytext AS post_content, title AS post_title, 0 AS post_category, hometext AS post_excerpt, 'publish' AS post_status, 'closed' AS comment_status, 'closed' AS ping_status, '' AS post_password, storyid AS post_name, '' AS to_ping, '' AS pinged, FROM_UNIXTIME( published ) AS post_modified, FROM_UNIXTIME( published +43200 ) AS post_modified_gmt, '' AS post_content_filtered, "" AS post_parent, '' AS guid, '' AS menu_order, "" AS post_type, '' AS post_mime_type, 0 AS comment_count FROMxoops_stories
SELECT "" as rel_id, storyid AS post_id, 1 as category_id FROMxoops_stories
Since I can't find any other source of conversions out there, I can't guarantee this will work because I myself am not familar with Xoops.
Try importing this into your SQL database.
1) Log-in to myPhpAdmin
2) Backup database and all relevant files.
3) Look for a button called Search query.
4) Paste the following code into it and hit go. (Do this seperately for those two code groups A&B)
Hopefully, you won't run into any errors while running these commands, as that's the best interpretation I can get from reading that link.