What am I missing / looping

Hey guys, I'm struggling with looping tbh. Ive used Ableton for years but trying to get into making beats live. That ari@home guy has really inspired me to change it up. I don't get how everyone seems to just play four bars or whatever and it auto loops immediately. I must be missing a setting somewhere because my loop starts off beat every time and I have to go an manually edit ityk be in time again. Any help is greatly appreciated