What is the auction procedure?
Let's see, the roll of the public auction is basically as a giant market, but instead of shouting "at one, both, sold!", Everything is more formal and with papers. Public entities - helping, ministries and all that rock - they know the purchase of things (they can be from bolis to bridges, you do not believe) and what they are looking for, obviously, is to pay as little as possible. So simple: the one who offers the same but cheaper, takes it. Well, almost always.
The move begins when they publish an ad - role "is looking for a company that does such a thing." There all the details release: what do you want, how you have to participate, dates, and all the fishing. Those interested (or brave, as you look) prepare their offer and deliver it in a closed envelope. No traps. Then, in a public meeting (which can be as boring as it sounds), the envelopes open and, in theory, which put the lowest offer and meets everything, wins.
But be careful, it's not just a matter of being the cheapest. Do not think that this is a Black Friday of the administration. They also look at things like quality, if the company has experience, if you can deliver on time, if you have solvency ... it is not enough to throw the price for the floors and now.
If you have a company and want to launch yourself, get well. Read the call as if it were the horoscope, do not leave a comma. It presents an offer that grinds and duning it to fulfill all the deadlines. If you can, look for a lawyer or someone who knows the subject because paperwork can be hell and there are norms that can catch you by surprise.
In case you are one of those looking in Google before all, eye with the keywords: public tender, public auction, lower offer, bidding announcement, presentation of offers, evaluation criteria ... and also are worth: public tender, lower bid, bidding process, etc. All that will come out a thousand times when you investigate.
Of course, each country has its rules. In Spain is the Public Sector Contract Law. In the US, the famous federal acquisition regulation. And each one has its own labyrinth of rules, so be careful to trust you and think that everything is the same everywhere.
In short: If you are going to get in these waters, see well prepared and not improvised. Find out, seek help if necessary and do not jump the rules, because the administration has no mercy and can leave you out for nonsense. And if you have doubts, you can always pull experts on the subject, which are for something, right?