Once you have installed and configured the Resco Mobile Solution in Dynamics 365, you can use the Resco Mobile Client.
The client can be downloaded on Smartphones. Click on this link to find the links to your phone app: https://www.resco.net/support/downloads/
Select to Install:
Select Internal User:
Enter your credentials, i.e. your Dynamics 365 URL, email login, password. Press the refresh icon in the top right, and you will then be connected to your Dynamics org and it will sync with your mobile app:
Once complete, you can select different entities, e.g. Accounts, to view records: