SAP implementation is a huge project. It takes a considerable amount of time depending on the size and scale of the implementation. Sometimes it takes more than 2 years to complete a SAP project. However 7-8 months time will be sufficient to fully implement SAP for a mid sized company. There are five main phase of a SAP project. (This is the general and most common definition. This can be changed depending on the different situations of the project and company.)
1. Project Preparation
2. Business Blueprint
4. Final Preparation
5. Go live and Support
Preparation phase is the initial planning of the project. You need to evaluate implementation partners and choose the right implementation partner, define the scope of the project roughly,evaluating vendors, buy SAP license, assign human and other resources etc.
See whether they have SAP experience in your industry. Because knowing the business is critically important than knowing SAP. You need to study their SOWs (Statement of Work) carefully to evaluate their bids specially for the SAP customization processes.Some vendors are mentioning maximum number of cutomized RICEF objects (Reports, Interfaces, Conversions, Enhancements, Forms) in their proposals. Standard SAP needs to be customized to suit your business. Customizing is costly. Also it is important to evaluate the project duration, training programs an support plans proposed by each vendor.
An internal SAP team should be appointed to get their support for the project. Team should have members representing each different business process/department of the company. Better to choose the best person from each department for your team who can be used for change management processes.
Business Blueprint phase is the documentation of company's business processes and organizational structure in the way which we are going represent our business in SAP system. Functional specifications are generated in this stage generally. Realization is the developing the system according to functional requirements. This is the configuration of requirements of the Blueprint. Then you can do testing and adjusting in final preparation phase and go live with your new ERP system.