place you finger underneath youe eye, slightly pull down. Use a curved mascara brush and go from the roots. if you can apply eyeliner this will be easy. Practice will make you better but keep in mind that somtimes mascarra only looks good on the top eyelashes most ppl don't put it on the bottom. YOu have to have the right shjaped eyes to make it look good. Keep trying and good luck.
make sure there is not too luch mascara on the brush, look up, pull down the bottom of your eye a bit if you find that easier and slowly and carfully wiggle your brush down your lashes.
Once I've applied it on the top lashes, I use the tip to run along the bottom lashes, that way there is not so much mascara on the wand and it doesn't get clogged up.