How can I connect my LED strip lights?
Usually you use the two outmost connection points for +/- 12VDC on the strip ... and usually + and - leads are marked by printed labels on the strips at each seperation mark.

For connection from power supply to the strip you either use the premounted socket (if any is mounted at the end of the strip) or you solder the cables coming from the transformer / DC source onto the connection pads.

With the shopping list of your OP I would do the following wiring

            +-------------+              +-------------+                +---------.
           ~|             |+ ---------- +|  in     out |+ ------------ +|
 110/220VAC |  Mains/12V  |    12VDC     |   Dimmer    |   12VDC PWM    |  Strip  ....
           ~|  converter  |- ---------- -|             |- ------------ -|
            +-------------+              +-------------+                +---------.


The power rating of your ACDC converter is a function of the length of LED strip you want to use. If I am not mistaken - a single tripple of LEDs (the smallest separable unit) takes 60mA ... so all 300 LEDs (100 sections) would require as much a 6000 mA (6A)

The current limit of the dimmer is 12A which is fine for the whole strip.

If you are using more than -say- half of the strip I would consider more than 1 feed point to avoid voltage drops along the strip.