The Store module must be implemented before the Buy module can be used.
Start by putting in the details of your vendors using the vendor details tool. Make sure your vendor codes are long enough to be meaningful, and that they are consistent.
Next you can enter the pricelist for each vendor using the vendor pricelist tool. You do not have to use pricelists, but they make ordering far quicker and reduce the risk of error.
Now ensure that your staff understand how the purchase order options are used, and how purchase orders will be raised and received. Check that the system's initial purchase order and purchase receipt numbers are correct (using the manager module options initialize documents and add more documents).
Note that the Buy module will probably now take over some of the stock movements you are currently recording using the store module options. Your stores staff should be clear as to how the system will operate when the Buy module is introduced.
If you have a separate accounts system decide how you are going to pass purchasing details to your purchase ledger. The option receipts summary and transfer report has been designed to allow quick manual entry of purchase receipts into an accounts system. Alternatively if you are using Sage 50 or 100 you may be able to pass the data directly into your accounts package.
Start raising purchase orders, sending them to vendors, receiving goods and raising purchase receipts.
Teach your staff to use the purchasing reports to help them control and monitor the purchasing process.
Monitor the system and correct any errors made.
Periodically use the delete / transfer old items option to remove old purchase orders from the system.