I'll be glad to walk you through the steps on how to import the file:
Go to Settings and select Import Data.
Select Products and Services.
Select Browse to upload the file from your computer. Choose the file, and then select Open.
Select Next.
Map your information. Your Field represents the headers on your spreadsheet. From each drop-down ▼ menu, select the one that matches a field in QuickBooks Online.
Select Next.
If you see some cells highlighted in red, this means the cell is invalid. Check the cell in your spreadsheet and try importing again.
Select Overwrite all values for each product or service with the same name. Make sure everything looks correct because this can't be undone.