how can I create a manual filter in calc?

edit

You can create a "based on formulas filter", which will display only some matched values based on predefined test condition, but it will not be a realfilter. Here is the topic with example spreadsheet - https://forum.openoffice.org/en/forum... Also please find a sample file which is edited based on your needs. But I still insist, that you should better use Calc built-in filtering functionality, Auto Filter will be a nice solution or consider working with database.