1. Login to Online Check Writer and select Apps.
2. Click Wave and click Connect; then, you will be redirected to the Wave login page.
3. Sign in to your Wave account using the credentials.
4. Choose the company and click on Allow Access.
5. Click Import Payees and Import.
   

To import invoices from Wave, 

1. Go to Invoice from Receivables bar.
2. Click Import Invoices and select Wave.
3. Choose the company and update Import Settings: select Time Span and Download Filter.
4. Click Start Importing.