Child Theme Creation

Hi,

This is my first wordpress site and I purchased the travelwp theme from you in August. Since then I have been working on the site but I only found out about child themes this week while reading another web developers comments here. I would like to update my site but I am worried that I will lose all my work to date.

Can you please help me with this? I think I need to ceate a child theme and then perform the update. I should manage the update fine but I do not know where to start with the child theme.

Regards,
Pat