"There are just little things that only experience can teach you," Ms Murphy said.
"There are the three 'S's on this site — safety is the first one, speed is the second one and Shirley is the third one. When Shirley shouts, they know when to listen."
The task of putting up the tree has both positives and negatives according to Shirley, but worth it for the end result— tree lighting.
The tree is 27m tall to the tip of the star — more than six storeys high — and takes a team of 15 people to install the frame and the lighting, fluff the branches and hang the baubles.
In the past couple of years, Hamilton has been hit by rain and thunderstorms which has proved a challenge in putting the tree up ready for Saturday's lighting.
"It took us off site about four times this week with the weather."
"That's why I always allow the last two weeks of November to build the tree because of the weather elements. You just never know."
One of the positives for Shirley is when the tree lights up to the public for the first time, although she always prepares for something to go wrong on the night.
"Murphy's law remember, anything that can go wrong, will go wrong. I'm always on site when we flick the lights on for the first time.
"It's one of the best feelings when I stand back and see all these lights, especially the new lights, come alive and watch the crowd enjoy the show."
The tree recently had new lights brought in, and last year with the help of father and son team Larry and Eric Coufmann, they are able to be programmed to match with the music that is played.
Shirley said the volunteers who help lay out the lights is also a positive.
"The helpers are adorable, the riggers — we just love having them on site.
"It's just a great environment."
With Shirley stepping down, this year she has been shadowed by Stephanie Carey who will take over the role of leading the team to set up the tree.
"She's learnt a lot and still has a bit to go, but experience will teach her that."
Saturday's tree lighting will be Shirley's last in Hamilton. She and her husband are moving down south to Picton to retire, something she is looking forward to.
"It's just such a lovely town, and just a bit of peace and quiet now.
"I will miss this. If I wasn't moving I would have stayed on."