Add README

Author: sever-sever

README.md

@@ -1,2 +1,19 @@
 # vyos-build-arm64
 vyos-build-arm64
+
+To build VyOS arm64 needs an additional steps:
+```
+docker pull vyos/vyos-build:current-arm64
+git clone -b current --single-branch https://github.com/vyos/vyos-build
+cd vyos-build
+
+docker run --rm -it --privileged --sysctl net.ipv6.conf.lo.disable_ipv6=0 -v $(pwd):/vyos -w /vyos vyos/vyos-build:current-arm64 bash
+
+# Add required telegraf key
+wget -q https://repos.influxdata.com/influxdata-archive_compat.key
+
+sudo ./build-vyos-image iso \
+  --architecture arm64 \
+  --custom-apt-entry "deb [arch=arm64] https://repos.influxdata.com/debian/ bookworm stable" \
+  --custom-apt-key /vyos/influxdata-archive_compat.key
+```