The good thing about the guide is that the graphical interface allows you to choose which area of your property that you want to investigate the rules and how they apply to what you wish to do. The areas fall into the following categories:
Making changes to your garden does not seem the changes that will incur the requirement of making a planning application and in many case this is true. However, some changes to your garden will have to be processed through the Planning Department.
Start by looking at the UK Government's website at the Planning Portal. In a clear and well presented graphical interface the rules are clearly spelt out and can form an excellent basis for your project.
There are two ways to apply for Planning permission. It can be complete in writing and submitted to the appropriate authority or it can also be completed online at Planning Applications. In many cases a hand drawing of the plan is sufficient in cases such as having a conservatory built. Obviously measurements and descriptions are to be accurate but the Planners do not always require an Architect's drawing to give their permission for the build to go ahead. Guidance for all of this is given on the website.The "Need More Information" area of the Planning Applications is a wealth of information and will clearly lead you through all the development stages.