Partial answer because I feel like I'm on the right track and have just made a simple yet important error.
First, the board doesn't quite look like the game of Set! I know, but I think I can figure out what might be going on here. We have 'Available moves', which are cards that allow us to create sets along with the board above. Now I assume the way this is expected to work is that we can move from the 'Start' to the end arrow by completing sets, using cards from our available moves as the third pattern. To test this, I noted the set-completing card between each pair, drawing a red X when that card was unavailable. This leads to the image on the right, which shows all the possible cards and the number of times we can use them. The only valid path from start to finish is drawn in gold.
Because this is the only valid path, I seem to have confirmed my assumptions.
Assuming the above is correct, that leads me to the next step.
Following the path in order we have the following instructions:
Move the third letter to the end of the string
If any letters occur more than once, delete all but the last occurance
Double the whole string. Move the first letter to the end of the string
If two letters in a row are alph. consec, switch them. If three+ are, delete them
Caesar-shift the third letter back one, move to the front
ROT13 first and reverse the middle letters
Double alpha latest each time
Replace last letter with spelled out name
However, I cannot find a starting string that does not lead to gibberish. So far, I have tried
START (because it is written on the map),
SET (as it is the theme of the puzzle and part of the title), and
TIMWI (the person you've made this for), but it's all gibberish. Maybe someone else can find a word that works, or an error in my previous steps. Here are those strings with the rules above applied:
Excuse my formatting, I can't get lists to work in spoiler tags (and I'm new to this site, pointers would be helpful).