Connecting your Sendloop account with Optingun forms is very easy.
Go to Sendloop dashboard and click on your profile on top menu, select Settings. On Settings page, click on API Integrations tab, there you will have your API Key, copy that key.
Go to create or edit your forms and navigate to settings page, you will see a tab for integrations.
Click on Sendloop icon from the App list there. If you have not connected your Sendloop account yet then this will ask you for your Sendloop API Keys, if Key is already saved then it will go to next step directly.
Paste your API Key in Optingun Sendloop Integrations settings page, and click "Save and Connect Sendloop", this will validate your key and if its correct it will connect to your account and load your contact lists.
Select a contact List from the select box and click "Add Integration", your new Integration will be listed below that settings box.
If you want to add leads from this Optingun form to a new contact list, you can create a new List from Optingun dashboard. Enter the list name and select if you want Double Optin or Single Optingin for this List and click "Create and Add Integration"
Once this form is saved, your leads from this form will go the Sendloop Contact List you selected. And thats all it is to connect Optingun forms with Sendloop.
You can also watch this video tutorial about the same process.