[help please] Add event drop down instead of text input

[ExSpirit]

Can someone help me with coding calendar - add event (Post.template.php), so that it's not text input but two drop down menus. I want members to select two number (one from 1-24 and second 1-60) - I will use that as a time. After members submits that event, instead of subject time will be shown. It's kind of simple way, but I need some help with someone a bit more experienced with coding.