Understanding xplorer (aka AjaXplorer)

I am looking for a more convenient way of accessing logfiles and editing some config files on my NAS than via the SSH command line. I thought, AjaXplorer could do the job, but when I try to create a new repository it just complains that the folder is not writable. I have set the default rights to "Write only" to start with, but it still wants to write (apparently to create a recycle bin).

Now, I assume that I "simply" need to grant Xplorer the rights it wants, but I am neither sure whether this is a good idea, given that I basically want to access the entire file tree, starting at \ I suppose it is not a good idea to chmod all files and folders on my system...

Also, I am not sure how to do this since I don't know under what user Xplorer is operating and if I knew, I would be unsure how to grant it the rights without distroying things.

I have seen the instructions by sebus46 in this thread, but I don't quite understand them... I have created a new usergroup "userandadmin" and added admin as a secondary member but which user will have "userandadmin" as their primary group? 

Could anyone help me understand how I can work with Xplorer?