You can just start with the basics.
Hopefully, you have a mathematical background. Otherwise, you won't understand all the concepts at a deep level but you can at least achieve a practical understanding of them.
Try to find an introductory course online. You can also refer to some practical books and implement some of the suggested algorithms.
If you want a detail explanation of Data Science then do check out Intellipaat’s blog which will help you in understanding DS.
You can get a hands-on project by referring the following Data Science Courses by Intellipaat which will teach you Data Science from scratch.
And if you are more into videos then do check out the following video tutorial which will help you in mastering in the field of Data Science: