Hi Ben and welcome to IIS
The scope you have is very similar to my first scope. Don't be too concerned about having trouble with the 12mm eyepiece. My first scope had a 10mm EP that gave 90x and I couldn't see much with that. Just use the 20mm as it will give the best views. Having said that, if you do use higher power on the moon, try to observe the terminator which is the boundary between dark and light sides.
Does it have a finder? If it does take scope out in daylight, slip in the low power EP (MAKE SURE YOU ARE NOT POINTING ANYWHERE NEAR THE SUN!) and get the main scope to focus on any ditant object eg top of a light pole, a branch etc. Then line up the finder using its adjustment screws. Once this is done the finder becomes your helper to locate objects.
Equatorial mounts can be very daunting at first. Have you attempted to polar align? Even a rough polar alignment makes using it a little easier. If you are in South East Melbourne I would suggest linking with a club, 2 that spring to mind are the Astronomical Society of Vic and the Mornington Peninsular Astronomical Society. The ASV have a loan scheme which once you are a member allows you to borrow an 8" Dob scope for 3 months, really worthwhile!
Malcolm