Link to custom page with querystring parameters

How can I add a link to the Taks page that links to a custom page I made, but with the task ID as querystring parameter ? Or another way to get the ID to the custom page.

Thanks

Hi
Can you share a screen shot, need clarity

I cannot clarify this with a screenshot, but I will explain further.

I made a custom page that shows a list of tasks for the logged in user.
The idea is to add a link in each item of the list so the user is redirected to another custom page with the details of that task.
So I need a way to get the ID of the taks from one page to the other.

Add the href link to that task

<a href="/app/task/${task}" />