Purchasing Contracts/ Services - Cross Years

Dears

We have Purchase contracts/ Expenses that cover 3 years, what is the best
practice to enter them in Purchasing Module, taken into consideration that the
service that we need to buy will be realized cross the years like 3 years and
we should accrued them every month with the appropriate amount,..

Suppose we have Contract to buy a service for 36 Months, 36,000 USD, and
every month we should record actual 1000 USD that realized the service on that month,

What is the best practice to enter this contract on the Purchase Module/ EBS
R12.0.4, taken into consideration that we should reserve the budget cross the