# Data preparation

!> This page describes the **Machine Learning Manager**, a service of the ForePaaS Legacy Platform that is not available on OVHcloud Data Platform. See [the current documentation](/en/product/index).

Data preparation is the first step to any machine learning process. It is the step during which you will **specify your data source and the rules according to which it is turned into ML datasets**.  
ML datasets are modeled and stored as [tables that are automatically created in the Data Manager](/en/product/lakehouse-manager/tables/index) and fed with data from the source specified at the entry of your pipeline. Specifying the rows and columns of these tables is the gist of the data preparation step.

!> In order to better orchestrate data versioning, data can only be added to an ML dataset. You have the option to manually reset your ML datasets in your [pipeline preferences](en/product/ml/pipelines/execute/preferences.md?id=reset-datasets).

![machinelearning](picts/pipeline-dataset.png)

Data preparation is usually the first step you need to parametrize since the rest of the pipeline should be designed according to this choice. To enter data preparation, click on **Dataset** on your pipeline's main page.

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## Dataset generation

You can connect data from multiple sources - either within or outside of ForePaaS - at the entry point of your pipeline. This data must then be split into a train and a test dataset for the model to be fitted and evaluated.


{Manage source and train-test split}(#/en/product/ml/pipelines/configure/dataset/input.md)

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## Feature engineering

Good data preparation means selecting the correct features for your model. Learn how to add variables to your X and Y sets, and how to execute basic checks on the data content.

{Manage your features}(#/en/product/ml/pipelines/configure/dataset/features.md)

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##  Need help? 🆘

> You didn't find what you were looking for on this page? You can ask for help via the [OVHcloud Help Centre](https://help.ovhcloud.com/csm/fr-home?id=csm_index) or the [support guide](/en/support/index).

{Send your questions to support 🤔}(https://help.ovhcloud.com/csm/fr-home?id=csm_index)