The green Add-listing button is on the top right of the page. By clicking on it, the available categories will appear (Cars, motorcycles, spare parts, etc.). Selecting a category will display the available options. Once you have made your selection, you will then need to fill in the ad details (fields with an asterisk are mandatory), give a description and upload your photos.
To delete an ad, go to the Menu (top right of the page) and select My Ads. Next to each ad there is the Delete option.