Once you have authorised the MTD VAT as shown in this article

You can proceed to use MTD VAT in two forms. 

1. Direct MTD Submission 

2. Bridging MTD Submission

The direct MTD submissions can be used when you do your charity's bookkeeping within Capium. 

Bridging VAT Submissions can be used when you have your bookkeeping records outside Capium. This tool is also recommended to be used when you are submitting for multiple VAT periods.