Just try to ask them to input their numbers or grade, separated by a comma and then you can split on it.

var arr = prompt("Enter your numbers").split(",")

Or, ask prompt ten times

var arr = [];
for(var i = 0; i < 10; i++)
   arr.push(prompt("Enter a number");

If you want them to be numbers, just prefix prompt with +, so it becomes a number(provided they're actual numbers) or just do

arr = arr.map(Number);

The way you are doing it is close. You just need to put the prompt() outside the loop. Once you have the input to search, you then loop through your whole array of objects.

For example:

var nameInput = prompt();
for (i =0; i < array.length; i++){
    if (nameInput == array[i].name) {
       console.log(array[i].id)
    }
}

Small explanation

Since your prompt is in a loop that also loops your array of objects, there can only be 1 "correct" answer at that given prompt point - whatever index (array[i].name) the loop is currently on.

To see more of what I mean run your current code and type jef the first time the prompt comes up, Steve the second time, and Ryan the third time- this way gets your IDs, but is probably not your intended outcome.