Debugging and Monitoring uploaded STEP 7 program

Hello guys,

I have uploaded a program from S7-300 PLC and of course, all symbolic names and variables are lost (I think that is a feature of older PLCs with older memory cards, but not sure...).
Now, after I studying electrical diagrams, I know to which inputs majority of sensors are connected.
I have created symbolic list in which I manually entered descriptions for inputs and outputs. My plan is to make debugging easier. Now, what I need to do, to have option to monitor program with symbolic names? Should I perform download again?
I'm asking this because, when I choose PLC->Online, another window opens with naked PLC's addresses.

Can you give me any advice?

Thanks

The settings in the block editor View>Display With determine how your variables are displayed.