Need help with getting reading from Digital Prepaid Meter by RS-485 on PC.

i need help in getting different readings . we have different go codes for each value to enter on the keypad . for example . press 1 to see units consumed , press 2 to see units remaining , press 3 to see last recharge .
now we are provided with RS-485 port for that communication . i have an arduino uno , an rs-485 module to do this thing , i am basically not understanding how Rs-485 protocol works , and secondly , i have two codes which are not working , obviously i am doing it wrong , but i got the codes from this forum from another topic . i am attaching some pictures of things im using and my meter . and i want continuous values , like the moment 1 units falls in the meter , i get the value falling in my computer too .
furthermore , i need to know what drivers and software are required to do this tasks as well .

please help me.

attachments :
1- picture of technical parameters of meter .
2- connections i’m doing between arduino and the module.
3- module that i’m using.
4- arduino that i’m using

I would tend to get a USB-RS485 dongle for a PC (cost a few £ in UK) to figure out the protocol
Then work on the PC to Arduino to meter interfaces

yeah i was thought of that ! let me get a usb rs-485 , actually i ordered one , but then , they gave me the one with serial port to usb . which wasnt even working . im attaching the picture of it , tell me , is this the one you are talking about ?


if you search on ebay for "USB RS485" you will get many links for suitable dongles