Hi Snow.
Tenders vary greatly. Many will tell you many different ways and would not actually be incorrect. As it dpends on what has been asked of you.
They usually invite you, and you will have a leafelt or a set of papers on the information that you must include in with your tender.
Some tenders even state the maximum price that you are allowed to have as profit. Even the total price for the works.
Generally you need to provide a break down of everything.
Covering Letter
This will be an introduction of your company. What your goals and mission statement is. How you could meet the relevant demand or service. How you have relevant experiences and what you as a company can offer.
Company back ground. How you would handle the contract.
It might also include
Conduct of the Work/Methodology of how to go about the works involved.
Labour
Costs
Scope of works
NI
Insurance
Risk Assesments
I hope this is of some help.
Dave