[ANSWERED] How can I change a color and material of a part at the same time?

I need help with my script so far. I made the part green and the material grass. I want to 'fade' into a golden yellow and plastic (the golden yellow RGB is 203,167,68). First, I put this script in a part: https://pastebin.com/kT1rF5GR When I tested it, every time it lags and I only see the part at a point I didn't want it to be to- a golden yellow grass fading into a green grass. I wanted it to wait for about 2 seconds as well, but it looks like it didn't wait to transition. I'm not a very experienced scripter, so I need some help. I just threw the tutorials I found on the web together, oof.

Here's the script if you couldn't find the one I made in the text: https://pastebin.com/kT1rF5GR

Insert the script into a part and please tell me how to change it to work.