Sheets2GCal is a FREE add-on for Google Sheets to allow fast event creation from spreadsheets.
To get started please install the extension from the Chrome Web Store (or "Add-ons" -> "Manage Add-ons"), then open any sheet and authorize modifications to your calendars by opening Sheets2GCal in the "Add-ons" menu.
If you require personal support please consider purchasing a Sheets2GCal support subscription HERE.
Before using Sheets2GCal please ensure that you have at least the following columns in the first row of your spreadsheet: 'Start', 'End' and 'Title'. Please remember to set the Spreadsheet to the same Timezone as your Google Calendar.