RollQuest summary of the SRD 5.1 rules, not a quotation.
Channel Divinity (action): imbue one weapon you are holding with positive energy. For 1 minute you add your CHA modifier to attack rolls made with that weapon (with a minimum bonus of +1), and it emits bright light in a 20-ft radius and dim light 20 ft beyond that; if the weapon is not already magical, it becomes magical for the duration. You can end this effect on your turn as part of any other action, and it ends if you are no longer holding or carrying the weapon or if you fall unconscious.
RollQuest ships the D&D 2014 SRD as a content pack, on a 5e character sheet that does the maths - roll from the sheet and let the numbers work themselves out. Free to start.