Hello,
First of all, thank you for your purchase.
1) To add the read more button to posts, please go to importing rule settings in the plugin ‘Echo to Post Rules’ -> click ‘Settings’ for the rule you wish to edit -> go to ‘Generated Post Content’ settings field -> add the %%item_read_more_button%% shortcode in to the settings field (append this to the content that you have there) -> save settings -> import new posts.
2) You can limit the imported length of articles, using the ‘Limit Article Word Count’ settings field, found in the same settings panel as the one linked in the response from point 1 from above.
Regards, Szabi – CodeRevolution.