The correct address book entries are:
173.145.5.21/255.255.255.0
203.150.108.10/24
Both of these entries represent a valid IP address and subnet mask combination, which can be used as an address book entry in a Juniper device.

By default, TCP has a 30-minute idle timeout, and UDP has a 60-second idle timeout.
Additionally, known IP protocols have a 30-minute timeout, whereas unknown ones have a 60- second timeout. Setting the inactivity timeout is very useful, particularly if you are concerned about applications either timing out or remaining idle for too long and filling up the session table.
According to the Juniper SRX Series Services Guide, this can be configured using the 'timeout inactive' statement for the security policy.

The policy is defined from-zone Trust to-zone Trust, which means traffic is controlled within the same security zone, making it an intra-zone policy.

The number of concurrent Secure Connect user licenses that an SRX Series device has by default is 2. Secure Connect is a feature of Juniper SRX Series devices that allows you to securely connect to remote networks via IPsec VPN tunnels. Each SRX Series device comes with two concurrent Secure Connect user licenses by default, meaning that it can support up to two simultaneous IPsec VPN connections.

Generate a self-signed certificate (or use a CA-signed one) to allow the SRX to decrypt and inspect SSL traffic for web filtering.
Configure an SSL proxy profile to enable SSL inspection, which is required for NextGen Web Filtering to identify and control encrypted web traffic.