Prerequisites
Three things are genuinely required before you can build a Zap, and they take a few minutes between them.
What you need
A Zapier account. Free or paid both work. The tier decides how many operations you can run per month, which only becomes a consideration once a Zap is handling real volume. Sign up if you do not have one.
A running Dime.Scheduler instance. Production or sandbox, either is fine.
An API key. Create it under Administration → API Keys (production / sandbox) and give it a name that identifies what it is for, such as "Zapier integration". A key named after its purpose is one you can revoke later without wondering what will break.
The full key is displayed once, at the moment you generate it. Copy it into your secret store immediately, because there is no way to retrieve it afterwards. Treat it like a password: never commit it to version control, and regenerate it if it is ever exposed.
What will make it go more smoothly
Neither of the following is required, but skipping them is where most of the avoidable rework comes from.
A working grasp of the data model. Zaps map fields between systems, and mapping them correctly means knowing how jobs, tasks, resources and appointments relate. How it works covers the terminology and how the pieces fit together in about ten minutes, which is considerably less than debugging a Zap that creates tasks with no job to hang from.
A sandbox to build in. Point your first connection at the sandbox instance and use representative test data. A Zap that loops, duplicates, or deletes the wrong thing is a curiosity in sandbox and an incident in production. Move to production once the Zap does what you expect, by creating a second connection rather than editing the tested one.
What you might add later
Zapier's value is mostly in what sits between the two ends. Spreadsheet tools for lookup tables, communication apps for notifications, and the other business systems in your stack all become available once the connector is in place.
Familiarity with REST APIs, JSON, ISO 8601 dates, and Zapier's own concepts (triggers, actions, filters, paths) helps when a Zap misbehaves, though none of it is needed to build one.
Next: installing the connector.