If you tick two options within one filter parameter, then this is treated as an "or" search, meaning either of them could be true. But if you tick two filters for two different parameters then this is treated as an "and" search, i.e. both parameters must be true to return a result. If anything is unclear about how the filter and search combinations work, just contact us: firstname.lastname@example.org
You can run the country filter for the projects by clicking on “Select countries”. However, if you want to combine the country filter with another filter parameter, then you need to operate the “apply filter” button twice: You need to firstly filter by country, then secondly filter by the other filter parameter(s) (or vice versa). To run the filter you need to click on the “apply filter” button.