Adding a fort to "descr strat"

How do I add a fort to the imperial campaign/descr_strat.txt so it appears when I start a campaign?

This question, like so many others, has already been asked. Please use the search function. The last version of this question was asked less than 3 weeks ago in this forum. Here's the thread: https://forums.totalwar.org/vb/showthread.php?t=101048

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