If you were trying to change the permissions recursively to allow for everyone to read and write the files contained within the filestructure you would want to open a command line and:
This would make it so as "others" (i.e. not the original user or group it belongs to) could read and write to the file. This isn't a very satisfactory method however, and if you could explain why you want to do this then we could probably suggest a more secure method of allowing the files to be shared. Such as by the use of groups.