Changing battery advice 146

My 146 1.6 Junior is over 7 years old and the battery now needs to be
changed.
Is there anything that I need to know in doing this job so that
everything continues to work after the battery change ?
In particular how can I be sure the alarm and the remote locking will
continue to work if the electrical supply is interrupted ?
The radio has a reset button which needs to be used once the new battery
is installed and I have instructions for this.

Any helpful advice gratefully received with thanks in advance.

John Chapman