Gyms can have a lot of different equipment and it may be confusing to know what to use and how to use it.

Free weights

Any exercise performed with barbells or dumbbells. The weights are free to move in space, hence the name. Personally I think this should be the mainstay of your training with cables and machine work added in on top of this

Cables

All gyms will likely have cable set ups like this. Cables are very useful for certain exercises. Generally more useful for isolation style exercises that work a single muscle compared to free weights that are useful for compound exercise that work multiple muscles at once.

Machines

-Machines can be a great tool to use for a few reasons. There will be machines that mimic free weight movements (ie. A machine chest press similar to a bench press) and the benefit of the machine is more stability than free weights and also can be easier to learn than free weight exercises.

Some machines are great as the machine exercise cant be mimicked with free weights. A good example is a leg extension and leg curl shown at the bottom of the page.