Date sorting, rearrange columns & file export

Hello

1) We want the rows in the backend to have latest saved data to be first. So maybe date sorting. Now it is showing depending on the first column any field and in ascending order.
2) How can we rearrange the columns so the necessary columns can be seen first instead of clicking on the first column to show all results?
3) While exporting in csv and pdf the attached file data or file path is not exported instead in csv there is some characters appearing ????and in pdf it is blank. at least the file name or the path can be shown which is there at the backend.

Please help us
thanks in advance