Create custom modal popup

I want to create a custom modal pop-up that works in a similar way to gleam.io

Here is an example, https://gleam.io/phdQ8/secret-album-launch

However in my custom pop-up, it just has a few random actions, such as

1. Subscribe to youtube channel
2. Join telegram channel
3. Visit this website

Then - continue button, when the pop-up modal closes

The modal does not actually check if the user completed the actions, like on gleam, it just waits a short while after each click and then allows the user to continue