Changing transmission on automatic VH motor

[1958FC]

This will probably seem like a really silly question, but I haven't been able to find a copy of a manual online, so I'm risking looking dumb here instead

I have a 1958 FC Holden that was fitted with a blue motor (VH 3.3) and an auto-transmission some years ago, before I bought her.
Recently the transmission has started to get obstinate about changing into "Drive", so I figure I need to first of all check the transmission fluid, but I don't know where it is on this motor or exactly what I should be doing with it. I presume there will be some type of dipstick and level gauge under the bonnet?
I don't want to pay a mechanic to do something that is probably just a simple fix.

I am no mechanic but I do know a wee bit about some car stuff; and yes, I AM a girl....

Any help (without making fun of me) would be appreciated. Thanks

[VK SL 3800]

Yep, there should be a dipstick up the back of the engine on the left side if your standing at the front of the car, you need to have the engine warmed up and running with the transmission in neutral to give the correct reading.

The colour should be nice a red, a more orange or dark colour can indicate its in need of changing.

[1958FC]

Thank you - I'll go check it right now! I really want to take her out for a long drive this week but won't chance it if she needs more serious work.
Hopefully, a top-up is all that she will need

[commy vk]

Hi there,+1 for sls answer.

[1958FC]

Transmission is a "Quicksilver" (whatever that means)