I cannot enter employee expenses - It always takes me to T777S. What I really want is to enter employee expenses without a slip

If your employer didn't give you a T2200, then you must use the T777s. It will ask you questions to verify if you are eligible, and then give you the choice to use the Flat Rate or the Detailed Method. If you want to claim the $2/day for your work from home expenses, choose the Flat Rate.