To access client activity log, first you have to open Clients. For that, click on Clients on left menu.
After you click the Clients, the system will direct you to the client page. To search your particular client, you can click the search button and type your client name, after that enter to search your client name.
After your particular client showed up, click your desired client.
Now you are in the client profile, after that, click on Activities to go to the activity log.