Advise me on the brake Master

Here is a guide that will help replace the master with step by step instructions:

https://www.2carpros.com/articles/how-to-replace-a-brake-master-cylinder

Also, how to bleed the system as this will be needed as well.

https://youtu.be/w7gUsj2us0U

Lastly the process below is from the manual and that will help with replacing this as well.

Please let us know if you have other questions. Thanks