How does form buttons can select checkboxes in the next page?

I have some buttons in a first_page.php, and some checkboxes in a second_page.php.

I need to select the corresponding checkbox with a query string to get this:

When "first value button" is pressed --> "second_page.php" with "my first value" checkbox already selected.

first_page.php :

<form action="second_page.php">
<input class="btn" type="submit" value="first value button">
<input class="btn" type="submit" value="second value button">
<input class="btn" type="submit" value="third value button">
</form>

second_page.php :

<form name="name" method="post" action="#">
  <input type="checkbox" name="mybox[]" value="my first value"/>
    <span>my first box</span><br />
  <input type="checkbox" name="mybox[]" value="my second value"/>
    <span>my second box</span><br />
  <input type="checkbox" name="mybox[]" value="my third value"/>
    <span>my third box</span><br />
</form>