WordPress is a user friendly platform for updating and maintaining your site. However, it is not a custom made platform exclusively for you. This means that there are many options available that your website and you will never use. For some, this can be very confusing. Using options that you are not familiar with can create unexpected results.
Our recommendation - don't take it for granted. You DO need an introductory course before you can start moving things around. It is a very powerful tool with many options and alternatives, so you must be carful with the changes you perform and register them in case you need to go back again.
Here is a very basic introductory tutorial - and we suggest you look for some others related to your needs.