You don’t “get” DoFollow links. The site sets its own parameters about whether links in their comments are DoFollow or not. You can’t influence that, other than to go site by site and look at their source code.
This is early 2000’s link farm strategy sort of stuff. Most decent sites disabled this with NoFollow because the outbound links were draining their page authority and made their site seem somewhat Spammy to Google. Find actual directories and get your backlinks properly.