In case you cannot see the CellBIM tab in ribbon then:
Go to the File > Options > Add-ins > scroll in the main table and you will find it under the "Disabled Application Add-ins"
Go to the "Manage" > Click on the Disabled Items > Go
Find the CellBIM > Select it and the click on Enable button
Ensure the Add-In is Installed Properly:
If the add-in is not listed in the available add-ins, it might not have been installed correctly. Reinstalling the add-in might resolve the issue.
Check Ribbon Customization:
Go to File > Options and select Customize Ribbon.
Under the Main Tabs section, ensure that the CellBIM tab is checked. If it is unchecked, check it and click OK
Check Excel Trust Center Settings:
Go to File > Options and select Trust Center.
Click on Trust Center Settings, and then choose Add-ins.
Make sure that the settings allow the loading of add-ins and that there are no restrictions that might prevent CellBIM from appearing in the ribbon.
Restart Excel:
After checking the above settings, restart Excel to ensure any changes are applied and that the add-in tab appears in the ribbon.