Best way to handle multi year opportunities

Best way to handle multi year opportunities

Hi All, apologies, looked for an answer to this but can't find one...yet I figure can't be the first person to ask this.
 
What is the best to log a 5 year opportunity?  I'd like to keep the same lifecycle number as the unique opportunity reference number.
 
Situation is that I'm putting together a proposal that cover the next 5 years, however the client will place an order each year for that year's work, so in terms of revenue reporting against the opportunity, the opportunity is say $100,000 but the revenue is $20,000 per year.  What's the best way to log this opportunity in Zoho?
 
Advice and suggestions much appreciated.
 
Nigel