We recommend that you always use a specialist advisor when making or updating a Will. They have the expertise to ensure that the wording clearly expresses your wishes and that it is legally valid.
Before your appointment it can be very useful to make two lists. One of these should be of your assets, things like property, shares and objects of value, and one of people and causes you wish to leave something to. Your specialist advisor may give you their own form to fill in prior to your meeting.