Dave serves us with his work on https://daveismyname.com/adding-events-to-microsoft-outlook-from-php-using-ical-bp regarding how to create a ics file form a link. Thanks to him!
I tried to ask him my question but had problems in display my code so I put it here on stack.
Could anyone be so kind and not down vote my even if it is stupid question (for everytime I try to ask something about php this happens)? I am a php newbie and trying my best to be precise! Thanks for patience!
So here my attempt with Daves code:
I use the following in my php calendar template page (WP using “Advanced Custom Fields Pro” plugin to set the data (which works just fine):
                  <div id="wrapper">
                     <?php 
                        $rows = get_field('events');
                        if($rows)
                        {
                            foreach($rows as $row)
                            {
                                echo '<a class="entry-meta-area" href="ical.php?date=' . $row['date_short'] . '&subject=' . $row['event'] .'&">      
                                        <div class="left-div">
                                            <div>
                                                <span>' . $row['date_long'] . '</span>
                                            </div>
                                        </div>                                                
                                        <div class="right-div">
                                            <div>
                                                <span>' . $row['event'] .'</span>
                                            </div>                                  
                                        </div>           
                                    </a>';
                            }
                        }
                        $date      = $_GET['date'];
                        $subject   = $_GET['subject'];
                        $ical = " BEGIN:VCALENDAR
                                  VERSION:2.0
                                  PRODID:-//hacksw/handcal//NONSGML v1.0//EN
                                  BEGIN:VEVENT
                                  UID:" . md5(uniqid(mt_rand(), true)) . "myspecificwebsite.com
                                  DTSTAMP:" . gmdate('Ymd').'T'. gmdate('His') . "Z
                                  DTSTART:".$date."T100000Z
                                  DTEND:".$date."T100000Z
                                  SUMMARY:".$subject."
                                  END:VEVENT
                                  END:VCALENDAR";
                        //set correct content-type-header
                        header('Content-type: text/calendar; charset=utf-8');
                        header('Content-Disposition: inline; filename=calendar.ics');
                        echo $ical;
                        exit;
                    ?>
                </div>
This creates 3 problems on loading the page:
1) Opens my calendar (Mac) on page load instead of on click the row where the data should be collected 2) My calendar gives a warning “could not read the file because no event is defined“ 3) Clicking the link leads to (404) page: …myspecificwebsite.com/calendar-template/ical.php?date=02/26/2016&subject=Annual%20Turnover (should stay on the same page, yet)
