You have a couple of options:
Firstly, if you have a developer (or are a developer yourself), then you can create a custom integration between Asana and Slack. This is good because it will allow you to have a little more control over how you integrate the two together. However, this’ll likely be the most costly and time consuming.
You can find the Asana API documentation here:
and the Slack API here:
If that isn’t feasible, then a third-party option is probably best for you. They’ll help you integrate the two together without knowing how to code. I run a service that does exactly that, integrates web apps together, and Asana and Slack are two of them.
It wouldn’t take much to add alerts for when a file is added or updated on a task in Asana, and I’m happy to prioritize it if it would be of help to you. If you’re interested, please head to https://www.getquickflow.com/pioneer and leave your email address and I’ll be more than happy to add that specific feature.
You can see the service itself at https://www.getquickflow.com. I hope this helps, good luck!