Assuming a two-tailed critical value, here are the steps in getting the critical value.
1. Convert the given confidence level to decimal form.

2. Divide the result by 2

3. Using the standard normal distribution table, locate the z-value that has an area of 0.48 from the center.
The z-value that has an area of 0.48 from the center is ± 2.054. Hence, the critical values are z = -2.05 and z = 2.05 for two-tails at 96% confidence level.
Assuming a one-tailed critical value, here are the steps in getting the critical value.
1. Subtract 0.5 from 0.96.

2. Locate the z-value that has an area of 0.46 to the right of the center using the Standard Normal Distribution Table.
The z-value that has an area of 0.46 to the right of the center is 1.751. Hence, the critical value for one-tailed at 96% confidence level is 1.75.
To summarize, we have: