If the Lansweeper Server service is running in Windows Services and you haven't made any changes to the LsPush files, the files will automatically be imported when placed in the Import folder and subsequently disappear. This process should only take a few seconds per file.
Keep in mind that LsPush only works if you have a valid Lansweeper license. If you are working in freeware mode instead, this would explain why the files are not being imported. You can contact sales (https://www.lansweeper.com/contact-sales/) to request a full trial key. (Make sure to send your email from a company email address.)