Find information about contracting with Hennepin County, including processes, forms, and diversity rules for goods and biddable services. Bids are generally submitted in the county's electronic bidding system, Supplier Portal.The Bidding Requirements consist of the Invitation to Bid, Instructions to Bidders,. (2) Conditions of the Contract for Construction (General and Supplementary);. Bidder must provide one (1) copy of the Proposal form. Bidder must only submit bid information in the designated areas of the Proposal form. Contractors must fill out the ATP-2 Form and submit NYSDOL. Contractors wanting to bid on items included in a particular letting must submit the properly completed "Request for.