If you want to edit a file(s) first find the file you want to edit then double click on it, it will then open the file in a built-in text editor if it is a supported file type, if the panel does not recognise the file type of the file you are trying to edit it will ask if you want to download the file.
To upload files to your server you can drag the file from your desktop then drop it on the file manager and it should upload the file for you.
If you have uploaded a compressed file or there is a compressed file you would like to extract on your server you can right-click the file then select Extract from the menu to extract the file.
You can also compress files by right-clicking on the file/folder and selecting compress from the menu. This will then generate a compressed zip of the files/folders you selected.