Hello Kristen,
unfortunately the options for creating a Watch Event module in Fusion are a bit limited.
Besides the fact, that you do not have any field available, it is also not possible to use the filter connector OR.
So, the field canStart is not there and I also do not know any possibility to find a workaround in that step.
The only solution I always use in such cases is to try to find a filter that restricts the triggering of the trigger at least a little and add an additional filter for the desired field on the way to the next module. This would mean, that you propably need to put a Read a Record module after the Watch Event and query the field canStart for the task. After that you can put a filter which checks for canStart=true and go on with your scenario.
I do not really like this approach, as through the Watch Event module a lot of unnecessary traffic is created.
Technically, when using the Watch Event module and creating a corresponding webhook, the Event Subscription API is used. Having a look in the documentation, you will see, how to create a webhook manually. Doing that, you would also be able to use any field as well as the OR filter connector.
Unfortunately I do not know any possibility to manually create a webhook and connect it to your Watch event module later.
I also did not find a way to modify an existing webhook, created by Fusion using the API yet.
Perhaps this is something for a support case.
Regards
Lars