After all configuration and installation complete, you have to build your application with capacitor, you have to use following command for signed apk
First, you have build for web changes with this command
ionic build
Secondly, you have to copy it for android with this command
npx cap copy
Lastly, you have to open android studio for build your signed apk
npx open android
If you face still any problem in build, you can follow this official link.
https://capacitor.ionicframework.com/docs/getting-started/with-ionic/