The front end holds the invitation to bid, instructions to bidders, bid form and bond forms. It also holds the general conditions, supplementary conditions and wage rates.
Example: an estimator opens the front end and finds the bid date and the bond requirements. The wage determination and the tax status are there too.
Read the front end before the technical sections. It tells you if the job has prevailing wages, bonds or liquidated damages. Each of those changes your price. Specialty bidders who read only their own section miss these terms and learn about them in the subcontract.