React native Android emulator error on Ubuntu 18.04

Hello! I am trying to setup react native to work on an android emulator.
I am using Ubuntu 18.04.
I am getting this error message when i try to use “react-native run-android”:

BUILD FAILED in 1m 21s
28 actionable tasks: 28 executed
Could not install the app on the device, read the error above for details.
Make sure you have an Android emulator running or a device connected and have
set up your Android development environment:
Introduction · React Native

Command failed: ./gradlew installDebug

Error: Command failed: ./gradlew installDebug
at checkExecSyncError (child_process.js:637:11)
at Object.execFileSync (child_process.js:655:13)
at runOnAllDevices (/home/william/react/AwesomeProject/node_modules/react-native/local-cli/runAndroid/runAndroid.js:299:19)
at buildAndRun (/home/william/react/AwesomeProject/node_modules/react-native/local-cli/runAndroid/runAndroid.js:135:12)
at isPackagerRunning.then.result (/home/william/react/AwesomeProject/node_modules/react-native/local-cli/runAndroid/runAndroid.js:65:12)
at processTicksAndRejections (internal/process/next_tick.js:81:5)

Furthermore, it says:

A problem was found with the configuration of task ‘:app:installDebug’.
File ‘/home/william/Android/platform-tools/adb’ specified for property ‘adbExe’ does not exist.

I found an answer that said to replace ‘/’ with '' in my settings.gradle in my react native project. The only thing in that is file however is:
rootProject.name = ‘AwesomeProject’
include ‘:app’

I solved it myself. Please remove this post.

I’m getting this error right now and don’t find how to solve it, can you tell how you did it please?