[Help]Sendkeys

hi im sorta new to VB and i need help wht im tryna do is press ames hotkeys for a game i play so if i tick just kill the mob on a vb forum itand i wnat it to press evry 15 seconds tab and f1
ive tryed
SendKeys.Send("{Tab}")
SendKeys.Send("{F1}")
but it doesnd seam 2 work in game..