I recommend you not to use this kind of pcb
Step 1: Led
Put the led some where on the board. Then bend the leads.
Step 2: Attach
Then attach the pcb to a holder or vise.
Step 3: Solder the Leads
Step 4: Cut!
Cut the leads and remember the negative and positive leads.
Step 5: More Soldering
Solder one lead to the led from a battery back max 6. Depending on led.
Next take the middle lead of the potentiometer and solder it to the negative lead of the led
Step 7: FINALY
Finally' solder one pin of the potentiometer to the other wire of the battery pack the add protection to the soldered wire.
Put in batteries and test