I want to add my tesc hudl tablet to the security but I was asked for a telephone number where do I find this?
If you mean it asked you for a "trusted number", that simply means a phone number that you trust. With remote features like Anti-Theft, the trusted phone number will receive alerts when the SIM card is changed in your device. It is also possible to locate/lock/wipe your device remotely in case it's stolen.
More detailed info: Mobile Security for Android - User's Guide
To download and install Mobile Security directly to your current Android device
If you are using the F-Secure SAFE portal on your Android smartphone or tablet you can download and install Mobile Security directly on your device.