National defense education bases need to follow corresponding laws and procedures when purchasing retired military equipment. The following are general procurement processes and precautions:

1. Understand relevant policies and regulations: First of all, you need to be familiar with the national policies and regulations on purchasing retired military equipment. This includes procurement procedures, procurement contracts, return and transfer of equipment and other provisions.

2. Contact the relevant military departments: get in touch with the relevant military departments to understand the types, quantity, quality and status of retired equipment. The required equipment can be obtained through bidding and competitive negotiation.

3. Prepare the purchase plan: prepare the purchase plan according to the specific demand and budget. Consider the use, specifications, quantity and other factors of the equipment, and make reasonable estimation and arrangement.

4. Bidding or negotiation: follow relevant procedures, open bidding or negotiation, and negotiate with retired equipment suppliers to ensure fair competition and reasonable price.

5. Evaluation and selection of suppliers: Evaluate and compare the bids or quotations, and select the appropriate suppliers. Factors such as equipment quality, maintenance and after-sales service can be considered in the evaluation.

6. Contract signing and payment: After reaching an agreement with the supplier, sign the purchase contract. The contract shall specify the specifications, quantity, price, delivery date and after-sales service of the equipment. Pay according to the contract

7. Delivery and acceptance of equipment: The delivery and acceptance of equipment shall be carried out in accordance with the contract. Acceptance shall ensure that the quality and quantity of the equipment meet the contract requirements.

The above is the general procurement process, and there may be some differences between different units in different regions. Therefore, the specific operation details need to refer to relevant laws and policies and communicate with relevant military departments.