Editing a Website

Good day guys, i’m just a newbie in wordpress and sometimes I dont know how to deal with it, specially today, As a part of my practice my friend give me an old copy of a website in a zip file and this the problem

1) We have a new image to add to the right of the page (the images like Cleaning for a Reason, ServiceMagic etc– that area)
2) We would like to add 2 additional photos to the main area at the top of the template.
Currently there is an image of a girl cleaning a kitchen, and we would like that box to flash between that current image and 2 others that we can provide to you.
3) We need to add an additional button at the top (next to the “Get an Estimate” and “Gift Certificate” buttons). This new button would be called “Request Booking” The new request booking button could be yellow with green writing.

My problem, where I’m going to edit this? in a texteditor or in wordpress(but how)

the site contains
wp-admin
wp-contents
wp-includes

please give at least a hint thank you.