Datatables Filter on first 4 columns

I have no experience with JS so please use small words!

I look at filter api, but my js skills are poor.

I want to filter the Datatable based on the first 1-4 invisible columns. (col1=?) AND (col2=?)... So could be just 1st col, could be all 4.

I would like to apply each filter request on button click event.

Could someone point me in right direction?

Also how to remove a filter?

thank you in advance for your help for my very noob questions.