Hi Isabel,
Many thanks for posting your IGI full instructions. It is interesting to see the various options for IGI searching all listed together.
However for less experienced IGI users, I hope you don't mind my adding the usual warning about the members' entries - the ones you have described as appearing in lowercase letters, where you may find "a lot more information on the page, such as date of birth and/or baptism, spouse, (and if you click on family) names and details of children. This is how you can build up your family tree. Try clicking on parents' names as sometimes their details are recorded too".
This information should always be checked against the original records (parish registers, wills, etc.) because the details, although a starting point, are often unreliable, and sometimes only guesswork.
The entries in capital letters are often extracted (transcribed) records from the parish register, and are usually reliable (except Death/Burial which may be attached to the wrong bapt). Clicking on the batch number then entering the surname won't necessarily show you relatives - it will show you people of the same name from the same parish, but it is a good start.
If you click on the Source Call No. for any entry it will show you where the record comes from.
Sue