You will need to download the import template (from the same page you upload the CSV to) and populate that spreadsheet with your asset details. Then export to CSV and import that.
You will need more info than just those fields in order to import:
For Windows computers you need to submit, at a minimum, an asset name, asset domain, asset type and state.
For non-Windows machines you need to submit, at a minimum, an asset name, asset type and state.
https://www.lansweeper.com/knowledgebase/importing-assets/