Step 1 : Click on Integrations tab in left menu, and then click on Add Integration button to add new integration.

Step 2 : Select Twitter from the select list and click on Save Integration

Step 3 : Click on Authorize App button on Twitter Auth Permissions Page [if you are not logged in into twitter you will be asked to login into twitter to view auth screen]

Step 4: Once you Authorize ContentLAB to access your twitter account, you will be redirected to Accounts listing page where you will be able to view the connected twitter account, this way you can add multiple twitter accounts into your contentLAB account.