Get the Dell OS10 Files here.
Get the Dell Sonic Files here.
After unzipping them. Open GNS3 and add a new template.
Choose Import an appliance file (.gns3a extension) and choose the switch from the folder you unzipped.
It will ask where to install (In my case Main Server is a GNS3VM)
Now it asks you Qemu binary (Machine Emulator), default is fine. Mine was qemu-system-x86_64(v4.2.1)
It will show the Appliance, the required files and if it is already or not on your Server.
Next is the import happening.
If this is the first time, it can take a while to import the corresponding VMDK.
The Appliance will installed under Routers.
These appliances are memory hungy (4GB per appliance, so a small VXLAN BGP EVPN lab of 6 machines requires at least 24GB of free memory)
First boot takes a while as it will effectively start ONIE procedure. And reboot afterwards again.
Default username: admin and password admin