# Set Up a Custom Library Prep Kit

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The Prep tab is deprecated and no longer available. For run planning and sequencer integration, see the [Run Planning](https://help.connected.illumina.com/basespace/sequence/plan-runs) section.
{% endhint %}

## Set Up a Custom Library Prep Kit

#### If your library prep kit is not available on the Libraries page, use the following instructions to create it.

1. When prepping a library, select + Custom Library Prep Kit in the Library Prep Kit dropdown menu. The Custom Library Prep Kit Definition page opens.
2. Fill out the name of the custom prep. It has the following requirements:
   * Unique for your account.
   * Characters: only alphanumeric, hyphen, underscores, and spaces accepted.
   * Less than or equal to 50 characters.
3. Select at least 1 of the supported read types.
4. Select at least 1 of the indexing strategies. Only selecting None is not allowed.
5. Fill out the default number of cycles.
6. Select template to download the index definition file template.
7. Fill out the Settings section the following way:
   * For single read only: no adapter (blank), or 1 adapter sequence for Read 1.
   * For paired-end: no adapter (blank), or 2 adapter sequences, 1 for Read 1 and 1 for Read 2.
   * Each adapter sequence meets the following criteria:
     * Sequence of A, T, C, or G character.
     * Length from 1 to 20 characters.
8. Fill out the Index1Sequences and Index2Sequences sections the following way:
   * For Single Index, with or without None: 1 to 100 Index 1 names
   * For each Index 1 name an associated Index 1 sequence
   * For Dual Index, with or without None and Single Index: 1 to 100 Index 1 names
   * For each Index 1 name an associated Index 1 sequence: 1 to 100 Index 2 names
   * For each Index 2 name an associated Index 2 sequence
   * Each index name meets the following criteria:
     * Unique within the file
     * Length from 1 to 8 characters alphanumeric, hyphen, or underscore characters.
     * Each index sequence meets the following criteria
     * Sequence of A, T, C, or G characters
     * Length from 1 to 20 characters
     * All index sequence lengths (Read 1 and Read 2) are equal
     * Index 1 sequences are unique within the file set of Index 1 sequences
     * Index 2 sequences are unique within the file set of Index 2 sequences
9. If the supported indexing strategy specifies Single Index, you can set up Default Layout By Well the following way:
   * Each well unique from A01 to H12
   * For each well, an associated index name exists in the specified Index1Sequences section
10. If the supported indexing strategy specifies Single Index or Dual Index, you can set up Default Layout By Column the following way:
    * Each column number unique from 1 to 12
    * For each column, an associated index name exists in the specified Index1Sequences section
11. If the supported indexing strategy specifies Dual Index, you can set up Default Layout By Row the following way:
    * Each row letter unique from A to H
    * For each row, an associated index name exists in the specified Index2Sequences section
12. Select the Choose.csv File button to select and upload your custom index file.
13. Select Create New Kit to complete the process.

Your custom library prep has been added to the library kit drop-down!


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