The manner in which you undertake your self-build may vary from a total ‘hands-on’, build it yourself, project; to a total ‘hands-off’, having a builder undertake the entire project on your behalf.
In all probability, the actual process employed will fall somewhere between these two scenarios. An increasingly popular self-build process is the managed project where you either appoint a project manager or act as project manager yourself.
Usually the role of the project manager involves engaging and overseeing separate trades, employed on a labour only or labour and material basis or a mixture of the two. When tradesmen are employed on a labour only basis the self-builder sources and supplies the materials.
Whichever route you choose, planning the process carefully is critical. This website outlines the major steps in this process from the initial idea to the completed house and highlights many of the options available.
Before you embark on your project you need to clear about your reasons for self-build (financial, design requirements, environmental, etc.) and be aware that these considerations may conflict with each other. Furthermore the process is likely to cause stress and have unforeseen difficulties.
Therefore ensure that you (and your family!) are prepared for this.