# Starting a new model-based custom entity type To start a new custom entity type: 1. On the **Custom Entity Types** page, click **Create Custom Entity Type**, then select **Model-based entity type**.

2. On the next panel, in the **Custom entity type name** field, provide a name for the custom entity type. 3. In the **Annotation guidelines** text area, provide instructions for how the model should identify values that you want to find. This is the first version of the model guidelines.

Panel to provide the name and initial guidelines for a model-based custom entity type

4. Click **Next**. Textual displays the **Test data setup** page. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.tonic.ai/textual/entity-types/entity-type-custom-model/model-entity-type-new.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.