learn to ollie

Well i just started skating like a week ago and made the choice of dedicating my self to it.There’s a big problem with my ollies though.I practiced them stationary for 2 days for like an hour or 2 and can get like maybe 3-4 inches.So i don’t know if thats good???Now i’ve decided to try them moving,I make several mistakes…The biggest one is when i go to pop the tail i go flying and the board sits there.(im guessing because when i pop it i leve my foot there to long or something.)The next problem i have if i do ollie while moving i can NEVER land it,Like seriously never.I fall off or the board goes flying under me and i bust my ass.Please anyone help me,I’ve dedicated myself to doing this even though i’ve just started.I will take any help thanks…