ADD customization button next to save button and edit button icon

i Want to add this 4 buttons with this icons next to save button
and when i press start it’s display the system time in other field and still count in this filed until i press finish even if i press save,

i try this code but it’s only have label and i can’t make the icon an it’s so small

  frm.add_custom_button("button lable", function() {
// code to be executed after button is click
}, "Button Group")

and this for icon’s but it’s to small too,“fa fa-play”), function() {