Net/30 is 30 days after the contract is signed in this case, Net/60 is 60 days. Sometimes instead of "after the contract is signed" it is "after work is deliver

Net/30 is 30 days after the contract is signed in this case, Net/60 is 60 days. Sometimes instead of "after the contract is signed" it is "after work is delivered" but my case was the former.