Integration between Salesforce and Appian

can someone please help me out with how i can go about the Connected System integration between Appian and SFDC.  I have read through the docs and I have to get key information from the App Manager ini SFDC.  My companys SFDC instance does not currently have Appian in the App Manager.  How do i go about getting the information that i need such as the consumer key, consumer secret key etc. from the App Manager?  Is this something that requires development on the SFDC instance?  I dont want to use the WebAPI approach (assuming that the connected system approach that was introduced in 19.2 has better functionality.)

Also, please note that the following link on this page https://docs.appian.com/suite/help/19.4/Connected_System.html#username-password-oauth-authentication points to an expired link in SFDC.  Please let me know.  

Username-Password OAuth Authentication

Provide a single Salesforce user’s credentials to authenticate. All integrations will use a shared Salesforce username and password. Individual Appian users do not need their own Salesforce accounts.

Please see Salesforce Username-Password OAuth documentation for more details.

Thanks