Retrieving Field name based on Maths

I have a Tiddler, that has fields with names (which can be tweaked) of level-0 through to level-5. In those fields I have numbers. (This gets rendered as a table in that tiddler.)

I have a different tiddler that is supposed to give an example of how to do something in the game, the example used to all be hard coded and we ended up with a load of mistakes before because no one updated the examples so I wanted to try and make it dynamic.

In the example, I need to combine two numbers, use that number to get the field from the table, then, do something else with that number after I get it.

I was able to do the combination of the two numbers in several different ways, but I failed turning that number into a fetch/get/transclusion of the next step.

https://starkingdoms.eaglesroost.org/#Operation%20Example%201