Follwong LinageOS instructions (here for Samsung Galaxy S III). You will have to adjust it as below and enter different command in device-specific code step.
https://wiki.lineageos.org/devices/i9300/build
Than create file:
/.repo/local_manifests/roomservice.xml
<?xml version="1.0" encoding="UTF-8"?>
<manifest>
<project name="S3NEO/android_device_samsung_s3ve3g" path="device/samsung/s3ve3g" remote="github" revision="lineage-14.1" />
<project name="S3NEO/android_kernel_samsung_s3ve3g" path="kernel/samsung/s3ve3g" remote="github" revision="lineage-14.1" />
<project name="LineageOS/android_device_qcom_common" path="device/qcom/common" remote="github" revision="cm-14.1" />
<project name="LineageOS/android_device_samsung_qcom-common" path="device/samsung/qcom-common" remote="github" revision="cm-14.1" />
<project name="LineageOS/android_external_stlport" path="external/stlport" remote="github" revision="cm-14.1" />
<project name="LineageOS/android_external_sony_boringssl-compat" path="external/sony/boringssl-compat" remote="github" revision="cm-14.1" />
<project name="LineageOS/android_hardware_samsung" path="hardware/samsung" remote="github" revision="cm-14.1" />
<project name="S3NEO/android_vendor_samsung_s3ve3g_samsung" path="vendor/samsung/s3ve3g" remote="github" revision="lineage-14.1" />
<project name="LineageOS/android_packages_resources_devicesettings" path="packages/resources/devicesettings" remote="github" revision="cm-14.1" />
<project name="LineageOS/android_device_samsung_msm8226-common" path="device/samsung/msm8226-common" remote="github" />
</manifest>Than run
repo sync
Clone manually
https://github.com/marcinguy/android_device_samsung_msm8226-common
and put it in:
device/samsungs/msm8226-common
At the device-specific code enter:
source build/envsetup.sh
breakfast s3ve3g
You are all set.
Good luck!