Trap Cards are purple Yu-Gi-Oh! Cards that have lots of different Effects. You can only activate Trap Cards one turn after you have Set them. After that, you may activate it during either player's turn. Trap Cards are Spell Speed 2, with the exception of Counter Trap Cards, which are Spell Speed 3.
You may chain Trap Cards to Spell Cards, other Trap Cards, or to the Effects of Effect Monsters.
Normal Trap Card
Normal Trap Cards are Spell Speed 2. You can activate it during either player's turn as long as you did not Set it this turn. The Effects of some Normal Trap Cards behave like Equip Spell Cards, but these Cards are still considered Normal Trap Cards.
Continuous Trap Card
Continuous Trap Cards are Spell Speed 2 as well. Their Effects are applied as long as they are face-up on the Field.
Counter Trap Card
Counter Trap Cards are Spell Speed 3. You can only chain other Counter Trap Cards to a Counter Trap Card.
Activate from Hand
Some Cards allow you to activate Trap Cards during the turn you set it or even from your hand.
An example is “Red Reboot”, which lets you activate itself from your hand by paying half your Life Points.