The account is required because MS Dynamics F&O requires an OAuth 2 authentication to be made prior to making API calls. The account in SnapLogic for the MS Dynamics F&O snap pack will have fields populated for the following settings:
This account is used by the Snaps in the MS Dynamics F&O Snap Pack.
You can create an account with a Designer or Manager. In Designer, when working on pipelines, every Snap that needs an account prompts you to create a new account or use an existing account. The accounts can be created in or used from:
Your private project folder: This folder contains the pipelines that will use the account.
Your Project Space’s shared folder: This folder is accessible to all the users that belong to Project Space.
The global shared folder: This folder is accessible to all the users within an organization in the SnapLogic instance.
Drag a Marketo Snap to the Canvas and click the Snap to open its settings. Click the Account tab. You can now either use an existing account or create a new one.
SnapLogic organizes and displays all accounts to which you have access, sorting them by account type and location. To select an existing account:
In the Account tab, click the icon to view the accounts to which you have access, and select the account that you want to use.
Click <Save_icon>.
In the Account tab, click Add Account below the Account Reference field.
Select the Location in which you want to create the account, select the Account Type, and click Continue. The Add Account dialog window associated with the account type is displayed.
Insert a GIF (max 500 X 500) demonstrating this procedure. See Configuring REST Accounts for reference.
Enter the required account details. For detailed guidance on how to provide the information required for each account type, see the following articles:
Click Validate to verify the account, if the account type supports validation.
Click Apply to complete configuring the <Snap Pack Name> account.
You can use Manager to create accounts without associating them immediately with Pipelines.
In the left pane, browse to the project in which you want to create the account and click 
> Account > <Snap Pack Name>, followed by the appropriate account type. The Create Account dialog associated with the selected account type is displayed.
Insert a GIF (max 1000 px) demonstrating this procedure. See Configuring REST Accounts doc for details.
Repeat the steps numbered 3 through 5 in the Creating an account section.
In Manager, you can navigate to the required folder and create an account in it (see Accounts). To create an account for MS Dynamics F&O :
MS Dynamics F&O Account:
Click Create, then select MS Dynamics F&O
Provide an account label.
Provide Instance URL, Client ID, Client Secret, Access Token, Refresh Token, Access Token Expiration
Supply OAuth2 Endpoint, OAuth2 Token, Authentication parameter, Authentication parameter value, Auto-refresh token
Click Apply.
Note: This account is used by all the snaps from this custom snap pack for getting access token information.