javascript - Selective overlay and expose with tooltips -

i want show first-time users different functions of web-app. this, want make in-page tutorial guide users through different parts of page.

i use tooltip modals instructional content. when modal showing, page element in question exposed while rest of page darkened. when user presses "next" on instructional modal, set of instructions show , part of page exposed , rest of page still dimmed.

what's best approach take this? please advise. thanks!