CreeperIclucia-Vader

I'm new to MOD dev and I'm trying to configure Forge environment.I did as README.txt told. Firstly,I opened build.gradle as a project in Intellij IDEA,and then I ran the command gradlew.bat genIntellijRuns. But when I tried to use the command runClient in IDEA, I was showed that "Module not specified" on net.minecraftforge.legacydev.MainClient. However, when I clicked 'run' and force it to run, I can still start the game with lots of errors and warnings.I tried many times and refresh the dependencies, reload the project or even repeat the whole process, the problem remains the same.I can't figure out how to make it right. The log is here: https://paste.ubuntu.com/p/D35YS4bTfN/