Import Meta Title & Description for Post

Hi, I’m preparing a CSV import from a website which its own bespoke CMS. All entries will be posts. For each post there is a meta title field and meta description. Ideally I want to eventually use this meta data in Yoast’s SEO plugin. What’s the best method to import the meta title and description for each post? Into a custom field?

https://wordpress.org/plugins/wp-ultimate-csv-importer/