They are not heavy I reckon. Have taken mine of a couple of times and I reckon my Sierra arb bar is heavier then the Jimny one.
Take the bolts out that detaches the bar from the chassis plates.
You don't need to take the chassis plates of unless you wanna paint them as well.
There are three bolts at each end if you just wanna take the bar off.
Two up inside the bar and one down below the chassis.
Should pull straight of then.
If you wanna take the hole thing of then I'm not sure just undo all the bolts and it shall come of eventually
Forgot to add it is better if you have a second person there to lift the bar to get the last bolts out. I managed on my own but for your safety it better to have help.