Ho to implement the vaxTrail function?

HI @mizanmahi !

Please write code directly into the forum instead of posting screenshots.
It is easier to work with that way.

When you enter a code block into a forum post, please precede it with a separate line of three backticks and follow it with a separate line of three backticks to make it easier to read.

You can also use the “preformatted text” tool in the editor (</>) to add backticks around text.

See this post to find the backtick on your keyboard.
Note: Backticks (`) are not single quotes (’).