Psuedocode is really just writing what your code does in English like statements. Pretend that I have no idea what your code is doing and explain it to me. There's your psuedocode. The obvious caveat is that you write psuedocode before real code but it's literally just a matter of describing what it is you need your code to do.
There shouldn't really be anything to struggle with there, so what exactly is it you're finding difficult? What have you tried so far?
There's nothing here to really understand, seeing you seem to be able to type English perfectly fine?
Check the specification or ask your teacher for some examples from the exam-board if you need a few hints.
Prompt user to enter first number
Check entered value is a number, store in variable A
Prompt user to enter second number
Check entered value is a number, store in variable B
Add variable A to variable B, store in variable C
Print variable C
There's nothing here to get, you're literally just describing what you want your code to do. I'm not going to write the psuedocode for you, as that doesn't help you. But I really don't understand the problem you are having. If you can describe what your code does, then you can write psuedocode. It's as simple as that.