You can use your reaction during other creatures' turns.
Roll d20 + Strength modifier (or Dexterity for finesse)
Roll d20 + Dexterity modifier
Roll d20 + spellcasting ability modifier + proficiency bonus
DM rolls d20 + target's modifier vs your spell save DC
Spell save DC = 8 + proficiency bonus + spellcasting ability modifier
Roll damage dice + modifier
Miss!
Follow-up suggestions:
Save Succeeds: Reduced or no effect (as per spell)
Save Fails: Full effect applied
Move up to your speed, before or after your action.
On your turn, you can move a distance up to your speed. You can use some of your movement before and after your action. For example, if you have a speed of 30 feet, you can move 10 feet, take your action, and then move 20 feet more.
Dash: move up to your speed again (uses Action)
When you take the Dash action, you gain extra movement for the current turn. The increase equals your speed, after applying any modifiers. With a speed of 30 feet, for example, you can move up to 60 feet on your turn if you dash.
Any increase or decrease to your speed changes this additional movement by the same amount. If your speed of 30 feet is reduced to 15 feet, for instance, you can move up to 30 feet this turn if you dash.
Quick actions: Mark resources as used if you don't need them.