To learn SAP, start with understanding the different modules of SAP like MM (Material Management), SD (Sales and Distribution), FI (Financial accounting), CO (Controlling), etc. Then, select your area of interest from logistics, financial, etc. and concentrate on that particular area. Enroll the well-structured online course with good real-time projects and go deeper into that area.
In case you are interested to learn SAP with hands-on experience, I recommend enrolling these SAP courses by Intellipaat.
You can watch this video to get started with SAP: