Vim3l not creating apk

1.I am trying to add new app in package which require to generate new apk at the time build.
2.I have added new app in package/app/ folder where every priv-app is present but it’s not generating apk which require service and framework.
3. How we can add new app package in vim3l which build and create for the apk as system app. Where we can need to add this app for the build.
4. I have created new app and added in package/app/ folder and added on generic_no_telephony.mk file for the build. It’s building successfully but it’s not generating apk for my application.Can you tell me where i need to add my app and how it will create my apk file.

in the device.mk you will have to add the apps that you want to have compiled with the rom.

@Pradeep_Kumar_Upadhy

device/khadas/kvim3l$
--- a/kvim3l.mk
+++ b/kvim3l.mk
@@ -471,6 +471,9 @@ AB_OTA_POSTINSTALL_CONFIG += \
     POSTINSTALL_OPTIONAL_system=true
 endif
 
+PRODUCT_PACKAGES += \
+    xxxx

xxxx==>Package name