trying to adapt a script to use qb-core, struggling

[beetwixin]

Sorry, newbie developer here. I am struggling to understand how to get the amount of money a player has in cash and their bank account and deduct it so that they may purchase an item.

Please see the snippet of code I am struggling with below. When I trigger this block of code I receive a script error, attempt to call a nil value (field ‘GetPlayer’). Is someone able to please point me in the right direction?

				local src = source
				local Player = QBCore.Functions.GetPlayer(src)

				BankAmount = Player.GetMoney('bank')
				PlayerCashAm = Player.GetMoney('cash')

				if PayWithBank == 1 then
					XNLUserMoney = BankAmount
				else
					XNLUserMoney = PlayerCashAm
				end

				if XNLUserMoney < TicketPrice then
					if UserBankIDi == 1 then -- Maze Bank
						BankIcon = "CHAR_BANK_MAZE"
						BankName = "Maze Bank"
					end
					if UserBankIDi == 2 then -- Bank Of Liberty
						BankIcon = "CHAR_BANK_BOL"
						BankName = "Bank Of Liberty"
					end

					if UserBankIDi == 3 then -- Fleeca (Default Fallback to!)
						BankIcon = "CHAR_BANK_FLEECA"
						BankName = "Fleeca Bank"
					end
					SMS_Message(BankIcon, BankName, Message[Language]['account_information'],
						Message[Language]['account_nomoney'], true)
				else
					if PayWithBank == 1 then
						-- Put YOUR code to deduct the amount from the players BANK account here
						-- 'Basic Example':  PlayerBankMoney = PlayerBankMoney - TicketPrice
						Player.Functions.RemoveItem('bank', TicketPrice)
						if Debug then print("FiveM-Trains: Ticket bought via bank.") end
					else
						-- Put YOUR code to deduct the amount from the players CASH money account here
						-- 'Basic Example':  PlayerCash = PlayerCash - TicketPrice
						Player.Functions.RemoveItem('cash', TicketPrice)
						if Debug then print("FiveM-Trains: Ticket bought via cash.") end
					end

					SMS_Message("CHAR_LS_TOURIST_BOARD", Message[Language]['los_santos_transit'],
						Message[Language]['tourist_information'], Message[Language]['ticket_purchased'], true)
					PlayerHasMetroTicket = true
				end

				IsPlayerUsingTicketMachine = false
			end
		else
			ShowedBuyTicketHelper = false
		end