Add data package requirement and cross-references

Co-authored-by: gewarren <[email protected]>

Author: Copilot

docs/ai/conceptual/understanding-tokens.md

@@ -103,6 +103,7 @@ Generative AI services might also be limited regarding the maximum number of tok
 
 ## Related content
 
+- [Use Microsoft.ML.Tokenizers for text tokenization](../how-to/use-tokenizers.md)
 - [How generative AI and LLMs work](how-genai-and-llms-work.md)
 - [Understand embeddings](embeddings.md)
 - [Work with vector databases](vector-databases.md)

docs/ai/how-to/use-tokenizers.md

@@ -24,6 +24,12 @@ Install the Microsoft.ML.Tokenizers NuGet package:
 dotnet add package Microsoft.ML.Tokenizers
 ```
 
+For Tiktoken models (like GPT-4), you also need to install the corresponding data package:
+
+```dotnetcli
+dotnet add package Microsoft.ML.Tokenizers.Data.O200kBase
+```
+
 ## Key features
 
 The Microsoft.ML.Tokenizers library provides: