Start with "concentration meditation", such as breath counting. Concentration meditation calms your nervous system ... but only while you are doing it.
It is training for the next type, which is mindfulness. The ultimate goal is to be mindful 24/7.
You gradually get better at catching yourself spiraling into anger, envy, impatience, etc. All the negative emotions that increase stress hormones. It takes a while to retrain your brain so that the limbic system is not so dominant.
Try doing everything in slow motion. Wash your hair in Tai Chi fashion, fold your clothes, load the dishwaher, etc. These are all opportunities to try to catch yourself rushing ... and intentionally slow down. Oddly enough, you will likely find that you get more done since you are not darting around like a squirrel :)
Google videos on "slow breathing". Not deep breathing. Deep breathing can lead to hyperventilation.