[Event Ticket Plus] Javascript to change form qty

I´d like to default to 1 the Event Ticket Plus form qty shown in the following screen capture http://prntscr.com/mwx4p9
I contacted the plugin creator and they told me that I could either create a custom template for the ticket form and change the "min" value on the field from 0 to 1. - OR - Add some custom javascript to change this when the page loads.
Sample Event: https://grumav.com/evento/intensivo-de-insercion-ecoguiada-de-cateter-picc-y-midline/

Also, I´d like to have an up/down arrow like the one shown in their demo page http://prntscr.com/mwx7fy
Demo: https://wpshindig.com/event/event-tickets-plus-demo/

Can you please help me choosing the best option and to achieve my goal?