Hello Rachael and Roo1 and weclome to the forum.
Rachael it certainly can be scary so maybe make your changes in habit a little at a time so it is not such a shock to the system. We are here to support you as much or as little as your need so sing out if you have any questions.
Roo1, unfortunately, there really isn't a one size fits all diet plan so sometimes there can be some trial and error as you work out what is a fit for you. Watching what you eat and how much is definitely a good start as well as adding exercise. Just remember to take it slowly if you haven't exercised in some time or at all.
You both may find it helpful to check out the various articles, tips and tools on the home page
if you haven't already as there are some great information on how to get started. We also have food and exercise diaries here in the forum to help you keep track of these things.
I wish you both all the best on your weightloss journey.