For Logo setting , Go to System > Setting > Edit > Images,
From Store Logo you can upload your logo image.

Thank You For purchasing Templatemela Opencart Theme.
If you have any questions, please feel free to contact us via our support form https://www.templatemela.com/support. Thanks again for your purchase.
For Image Size setting ,
Change Category Image Size to : 730 X 146,
Change Product Image Thumb Size to : 332 X 375,
Change Product Image List Size to : 205 X 195,
Change Additional Product Image Size to : 332 X 375,
Change Related Product Image Size to : 205 X 195,
Click on “Save” button.
For Example To add Spanish Language :
Go to System > Localisation > Languages,
Click on “Add New” button to add new Language.
Language Name : Spanish
Code : es-es
Status : Enable,
Sort Order : as you like.
Click on “Save” button.
For adding Main banners go to Design > Banners.
(disable HP Products Tab by clicking edit button)
Click on “Add New” button to add new banner.
Give Banner Name: Home Page Slideshow,
From status select Enabled,
and click on “Add Banner” button.
Give title of your banner and click on image to upload your banner.
Again click on “Add Banner” button and upload another banners.
Now click on “Save” button.
Go to Extensions > Modules > HTML Content > Install(After install click on "Edit" link),
For FooterBottom Payment CMS
Click on Add Module to add cms block.
Give Module Name: Footer-bottom-CMS
Now click on Code View button in text editor block and paste this code.
From status select Enabled,
For FooterRight Contact Us
Again Click on Add Module to add cms block.
Give Module Name: Footer-right-CMS
Now click on Code View button in text editor block and paste this code.
For Home-Aboutus-CMS
Again Click on Add Module to add cms block.
Give Module Name: Home-Aboutus-CMS
Now click on Code View button in text editor block and paste this code.
From status select Enabled,
Go to Extensions > Modules > Information > Edit (Click on Install link if Edit link is not there),
From Status select Enable,
Click on “Save” button.
Go to Extensions > Modules > Latest > Edit (Click on Install link if Edit link in not there),
Give Module Name = Home Latest
From Status select Enable,
Give Limit = 4,
Give Image size ( 205 X 195),
Click on “Save” button.
Go to Extensions > Modules > Latest > Edit (Click on Install link if Edit link in not there),
Give Module Name = Left-Latest
From Status select Enable,
Give Limit = 3,
Give Image size (80 X 80),
Click on “Save” button.
Go to Extensions > Modules > Account > Edit (Click on Install link if Edit link in not there),
From Status select Enable,
Click on “Save” button.
Go to Extensions > Modules > Affiliate > Edit (Click on Install link if Edit link in not there),
From Status select Enable,
Click on “Save” button.
Once again, thank you so much for purchasing the theme. We are glad to help you if you have any questions relating to this theme. You can contact us and submit technical Supprot Ticket from our support desk https://www.templatemela.com/support/