Here is a quick guide from Lightspeed that you can use to export your csv file: https://ecom-support.lightspeedhq.com/hc/en-us/articles/220319408-Exporting-order-data
Once you have that .csv file, you will be able to import to Shopify using the OrderImp service. Let us know if you have any other questions by reaching out at: support@orderimp.com