25HP Mariner oil check

[DMAK]

Hi
Total newbie so please bear with me.I have a 25hp 4 stroke Mariner - how do I check the oil level?. I see the yellow plug and assumed it was a dip stick but is just a cap. Do I rely on the alarm or what?

 

[racerone]

Look the motor over very carefully and look for the dipstick !