Create a web application to send sms to a group of people [on hold]

Create a web application to send sms to a group of people [on hold]

I have been given a project to create a web Application to send message to
a group of people via sms. After googling it i only found that php can be
used to do so but don't know how. Please can anybody help me where to
start. Can i somehow use way2sms.com to send? Please let me know how.