Automatic service order as a subscription

i would like to create a service item for annual maintenance contract in this conditions:
1- when the customer buy this service this should be be hold until the responsible approves that transaction.
2- once the responsible approves that it will be converted automatically to the technical tam as a monthly task to schedule this task to be 1 visit/month = 12 visits per a year
3- this item gives the customer a unique id no. for his equipment if he hasnt buy it from us.

it is my first time with ERPNext and i hope to find help.

can any one help me with this ?

with my greeting @umair it’ll be very kind to. have a look.

This is a volunteer forum, please don’t @tag folks for help.

To specify or point to what you have found and tried, and where you are stuck, would help here.

thanks for your contribution

i already created: item, subscription plan,
i added field: subscription plan to the item, so now i want to sell the item service as a subscription which is can be reflected in the subscriptions directly.
so how to link the item to the subscription?