Sarah unfortunately there is no guide/video for this right now, there should be one out by July.
In the example above, a trunk is used between the BIG-IP and the ACI Leaf. So physically it's a one arm but logically it's two-arm , since we using a different VLAN tag for external and internal interface
For one-arm
1) While creating the logical device cluster, under the 'Cluster Interfaces' section, specify just one interface and assign it a VLAN tag
2) When you create a graph template, you will get an option to have the template as 'one-arm' or 'two-arm', select one-arm at that point
3) Then apply the graph template (Specify the 'provider' and 'consumer' EPG', click next and assign the interface to the BD)
4) Assign the appropriate VLAN tag/Self-IP/routes on the BIG-IP