Most local authorities will provide plans and other documents for a planning application online. If not, you can ask the local planning authority to send you copies. Read everything thoroughly. If you don’t understand something, you can ask the case officer or look at Planning Aid Wales.
Planning permission is generally needed for any development. This means building, engineering, mining or other activity that makes changes to the use of land, or changes to existing buildings. There are exceptions that do not count as development, such as maintenance, changes to the interior of a building, agriculture, forestry and changes to gardens.