To get the “Help The Scientists” Badge and to find out the sample locations in Field Trip Z Roblox, you need to follow this guide:
Firstly, you will need to Play the Game Normally.
After some time, you’ll be able to go to Box’n’go. Collect the Food from there. 
After Donut Dave tells you to get back, you’ll see an Exclamation Point on one of the Scientists over here. Now you need to Talk to them. 
The Scientist will ask you to Find 3 Sample for them. You will find the one sample in the gutter by entering through its open hole. 
For other one sample, you need to climb outside the blue building. (It will be the terrace). 
After getting all 3 Samples, you need to play the Game Normally. 
When you reach the Part where you have to decide whether to Follow Dumpster Diver Dan or Donut Dave, you’ll meet the Scientist there. 
Wait until Dumpster Diver Dan and Donut Dave come here and a Cutscene will play. 
After collecting the 3 Samples and talking to the Scientists, you’ll get the Badge. 
