don't know why you would want it accessible on your router, but click the green button -> Download ZIP, you can then transfer the ZIP to the router, or wget the ZIP using the URL, obtained by right clicking.
Well there is a program which I need to run with specified MAC address which send HT sounding packets to that address. The directory contains both the send and recieve versions of the program. There is already another version of the program available by default on this modified version of OpenWrt firmware that I'm using but I'm trying to increase funtionality which is why I need to run this modified program.
Are you saying I'm able to access the router via the file manager?
I have tried using scp and I get an error:
scp: .: not a regular file
You should be able to run scp from a client on your pc to the router without any additional packages.
If you cannot find a proper scp client, then you can add package openssh-sftp-server in OpenWrt and use Filezilla on your pc.