After reading this blog, and watching the YouTube clip, you should have enough information to start figuring out how to use XMLPorts to import flat text files, even if this file contains data for multiple tables.
When I first got started as a NAV developer, I was assigned a senior whose job it was to educate me about what it takes to be an effective NAV developer. Whenever I had a question he would always challenge me to figure it out myself, while maybe giving me a tiny little push in the right direction. At first I thought that was very annoying, but it forced me to develop what is probably the most important skill as a developer: the skill of "figuring out how stuff works". Once he was satisfied that I had spent an adequate amount of time and brainpower to a problem, he would take the time to give me a lesson. Sometimes he would make these lessons up on the spot, because he had to figure it out himself. Those lessons are my favorite memories of my time learning how to be a NAV developer, and oddly enough most of them weren't even about syntax or objects, but about "how to figure stuff out".
Every day, I make my rounds through the online communities, in search of questions to answer. Sometimes, I find a question that makes me wonder myself how something works. When this happens, I take a standard NAV database, and spend some time in the evening hours to figure it out. The past few days there's been a question about how to import data for multiple tables into the RTC from a flat file, using an XMLPort. Now, at ArcherPoint all the developers attend a weekly conference call, and one of us presents a technology, or some tips on how to do certain things. We had recently held one about XMLPorts for the RTC, so I felt confident that this one would not be too big of a problem for me.
While my wife took my daughter to dance class, I worked on a couple of XMLPorts for the RTC, to import Purchase Invoice information into NAV. The YouTube clip below describes the results of those efforts. Hopefully this will help you understand how this works.
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