To install your theme in WordPress you must navigate to the menu "Appearance" on the left and then the submenu "Themes". From that page you should see your current theme "Twenty Fourteen" by default OR whatever theme you currently have. Now click the "Add new" button and then the text button at the top "Upload". You then should click Choose File and find your theme files on your computer and upload them. Note: You are only uploading the folder "landlr.zip" Your final step is to "Activate" your theme.
Getting your URLs to display page names instead of numbers
By default the pagenames will be website.com/p15 instead of website.com/about. To fix this go to "Settings" > "Permalinks" and my recommendation is to change the Common Settings to "Day and name". After choosing "Day and Name", Click "Save Changes" and your done. Your urls will now display a proper Permalink structure.