First step, press “Open Directory” and select a Metastock directory. A Metastock directory has a large number of small numbered files, each containing data for one stock, and files named MASTER, EMASTER and potentially XMASTER. You should then see, if the directory is a valid Metastock directory, the list of stocks displayed on the left table. On the right table, you can visualize the data, after selecting a stock.
Select (checkbox) the stocks to import, and press import.
If the stock already exists in the base, it is updated with the imported data. If the stock does not exist, it is created and stored in a “Metastock” portfolio.