An explanation text usually starts with a statement that introduces the subject or topic to the reader, such as;
'Lots of animals like hedgehogs, badgers and mice hibernate during winter.'
Next there comes a series of steps that explain how things happen or the reasons why, such as;
'This is because it gets much colder and darker during the winter months.'
'When it gets colder, food like berries and insects become harder to find. Therefore, some animals find a safe place to sleep and store energy until the plants start to grow again and food is more plentiful.'
These steps continue until the question has been answered or the explanation is complete.