Is it possible to profile a Trigger

Is it possible to use the Daml profiler to profile a Daml Trigger rather than a Daml Contract?

At the moment this is unfortunately not possible.

Where can the Daml profiler be accessed please?

The profiler is part of the enterprise SDK. You can find documentation on how to use it at Daml Profiler — Daml SDK 2.5.3 documentation.

As for installing the enterprise SDK, take a look at Installing the SDK — Daml SDK 2.5.3 documentation