Inside that folder should be one or more folders with random names. Copy the file(s) you want to import to your Android phone.
Find the one that does not have a timestamp (-Year Month Day-Hour Minute Second) at the end. You can use whatever transfer method you like, preferably USB, but Dropbox, Email, etc. The app works with any filename, so you may want to rename the message database file to something like sms.db, and the call log to to make it easier to identify them. If you use the original filename(s) or one of the ones suggested above, the app will find the files automatically and not prompt you to select the manually.
Better safe (and charged) than sorry (and having to start over).
If you select the later, it will show you the names of the contacts if you have already added them to your phone's addressbook, otherwise it will show you only the contacts' phone numbers.
If you plan on using this selective import, i highly recommend adding/syncing all your contacts to your phone before using i SMS2droid.
I would also recommend just letting your phone do its thing while the import is running.
The import should continue in the background if you absolutely have use your phone for something, but the general rule of thumb is: the less resources are used for other apps, the faster the import will finish.
If your Android version is very outdated or there are other reasons why you can't use the app, use the Online Converter and import your messages with the 3rd party app SMS Backup & Restore.