I've been weight training for years.. You'll need to get your body 'conditioned' sort-to-speak, before you start 'getting after it'. Even if you consider yourself reasonably fit.
This includes warming up. like simple calisthenics used in high school.
Start out light, easy reps (15-20) with compound movements. This will minimize soreness, and encourage you to stay with it.
Once you find your mojo, and your body will let you know when, you can start more aggressive routines and heavier weight.
Machines like you have are 'safer' for beginning, cause the weight is 'controlled' for you and reducing the risk of injury.
I also have a corner machine, with cables, I use along with dumb bells and bars.
Free weights are important too. They will incorporate more stabilizer muscles in the movements that will improve balance and agility.
It's a great lifestyle. Enjoy it, your kids will thank you.
