Query in order fulfilment

Do I need to provide this Token=”3eb9bae2-cae6-3925-bfd1-10b8dce40185” always whenever I hit any API and is this a constant value for entire application., and similarly after validating userid & password the “X-Seller-Authz-Token” that I got is always remain same whenever I login and again is this a constant value for entire application?
In Sandbox environment, whenever I hit any API (For ex : I have updated the order status PFF state to PRNT state, API return SUCCESS response), it provide me the SUCCESS response, but it does not reflect any changes in result panel.
When I access [/orders/completed] API in sandbox environment, I use any random order id or wrong order id then it still returns me the result instead of providing the status that wrong orderid provided, so how do I validate results at my end if always I provide wrong order id in [orders/completed] API.
According to documentation, is it mandatory to follow all steps for fulfillment of snap deal orders
• Get pending order details (/Order/new)),
• After that print the labels of the pending order ex (/orders/print)
• After an order has been printed, and physically packed, then items needs to be added to manifest. ( /vendorself/manifest)
• Once items have been added to manifest for handover to courier, print out of manifest needs to be taken. [Refer: /vendorself/manifest/print]
• After internal process and installation done on client site. [Dishtv process]
• After manifestation seller needs to mark the status of the items as delivered on successful delivery of the order to the customer. [Refer: /orders/bulk/status]
• In-transit and delivery statuses can be checked using completed orders API. [Refer: /orders/completed ]
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    Can we follow only these steps for fulfillment of snap deal orders 
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• Get pending order details (/Order/new)).
• After that print the labels of the pending order ex (/orders/print)
• After internal process and installation done on client site.
• Update order states successfully delivery . [Refer: /orders/bulk/status]
• In-transit and delivery statuses can be checked using completed orders API. [Refer: /orders/completed ]