I've recorded a quick how-to video on the process of importing and following the people you follow on Twitter in just 2 minutes.
You can use either debirdify.com or fedifinder.social to get your Twitter followed's Mastodon handles from their Twitter bios.
Here's the video.
https://kraut.zone/w/cUwEiUyivYWV1bhS5UD5rS
I've shared via kraut.zone, which is a peertube instance, a video sharing platform similar to mastodon.