Please help me to use my TI - 84 so I can get a radical number when working with larger numbers. the steps I must take and having the TI - 84 set to the right function

I am afraid I do not completely understand what you want. This calculator does not have a Computer Algebra System or CAS. So the results of all calculations will be displayed as decimal numbers, and that includes the square and other roots that are irrational numbers (square root of 2, 3, 5 7, etc.)

You cannot manipulate radicals on this calculator, whether for small numbers or large numbers. Sorry.