How to bleed the oil kerosene boiler

[rfltn]

Hi everyone, can you help me figure out how to bleed my boiler? I saw a thread where people were very helpful before but I'm not sure which bit I should be looking at!

Hopefully you can see these images:
ibb.co/kfjXc7
ibb.co/cSsJH7

I can also link one of the inside of the boiler unit (which is inside our kitchen, it's old).

Thanks in advance for your help!!

Here is the inside of the boiler:

ibb.co/n5Hcc7
ibb.co/bYQ2AS

I finally found the reset button hidden under a galvanised cover so I am hoping that will sort it! Waiting for it to come up to pressure now.