WPS spreadsheet help

I am creating an invoice for my small business record, with the use of WPS spreadsheet...
However I am very new to it and so far the only thing I am able to use is =sum() command
which sums up the prices of individual items.

In my invoice it basically consists of the basic customers' information and then a table
of the list of detailed items and services. In the table there are general things like
Product Name/Code/Unit/Quantity/Sub price etc....

I'd like to know if it's possible that every time I enter a few letter of the product name or product code
it will automatically show up the suggested products for me? And then if I choose one of the suggested product then it will automatically fill up the unit price of the item for quantity 1?

and if the quantity is changed to more than 1 it will automatically multiply the quantity with the unit price and then generates a sub total price?

How to do that? Is it difficult for someone like me who only knows =sum() so far...

Thank you all very much!!q

 

I believe in Excel that feature is something called "Data Validation" For example, skip up to 6m:29s into this video to see how Excel handles Data Validation and Lists -

Assuming that is what you want, search around for "WPS 'Data Validation' List" and see if you can find out more about that functionality within WPS.

Good Luck.