Architects, electricians, plumbers and carpenters: There are usually scores of professionals involved in building, renovating or repairing your home. That is especially true for major projects.
You would probably hire a general contracting company to coordinate. The people you hire may some or all of the work themselves. They may engage local partners to handle specific tasks. It usually depends on the scope and difficulty of your job, as well as the type of organization you hire.
Meeting different contractors
Contractors have that title for a reason. They work under formal agreements. As explained on FindLaw, a contract is a legally enforceable agreement — to do the work you need on your home, in this case.
Without this agreement, you do not have a deal. The contractors should not start working, and you should not expect or allow them to do so.
In terms of home repair or construction, your agreement will probably have to be in writing. These jobs usually take a long time and involve large amounts of labor or material.
However, the first step should be an estimate or a bid. The contractor should visit your home or site, discuss what you want and suggest costs. You should probably take notes during this meeting, so you can remember at least the time, money and materials you plan to use.
Formalizing the business relationship
After your estimate, the person you intend to hire would prepare a document for you to sign. This should outline everything you discussed, especially the time to finish the job and the costs involved.
Contractors typically do not have the inclination or the legal background necessary to explain all of the different clauses to you. They may simply comment that all of the complex language is standard, or that it is part of all of their contracts. You may need independent research or advice to confirm this — but that is typically easier and cheaper than pursuing a lawsuit.