JoJo480

Hello, I have a question about minecraft forge and hope that I can find an answer here. Here is my question: I have a mod that does not match my forge version. I would like to update forge! I watched a tutorial on YouTube and said that I just had to change the forge version in the build.gradle file in the explorer. However, it was not said where to find this file in the explorer! And that`s my problem I don´t know where to find the file in the explorer. I hope someone can tell me where I can find the file. Best regards J.