It's easier than it seems. These are your options for column headings:
product_parent_id | product_name | product_description | product_quantity | product_code | product_published | product_hit | product_created | product_sale_start | product_sale_end | product_delay_id | product_tax_id | product_type | product_vendor_id | product_manufacturer_id | product_url | product_weight | product_keywords | product_weight_unit | product_modified | product_meta_description | product_dimension_unit | product_width | product_length | product_height | product_max_per_order | product_access | product_group_after_purchase | product_min_per_order | product_contact | product_last_seen_date | product_sales | product_waitlist | product_layout | product_average_score | product_total_vote | product_page_title | price_value | price_currency_id | price_min_quantity | price_access | files | images | parent_category | categories_image | categories_ordering | categories | related | options
If you don't need a heading, you can skip it.
My shop is pretty simple, so my spreadsheet is simple. I'm attaching it for you to get an idea of how it works. I work with the spreadsheet in excel, but you must remember to save it as a CSV file. Additionally, I have an extra column, Color, that is for my info only. When I upload the csv, I get an error about this column, but ultimately it ignores it.
File Attachment:
File Name:
Book2.csv
File Size:22 KB