Hello, Niksamarkovic4,
It may be simplest for you to activate the WooCommerce plugin and import its demo pages. We recommend against running a full demo import to avoid a mix of your and demo content.
About the missing button here – https://imgbb.com/19Vds5C , it is not a typical problem, so to be able to answer, we need to check the settings on your site. Please provide URL and temporary wp-admin access.
Kind Regards,
8theme team