Need help replacing water hose on back panel of kenmore 90 series washer

That should be a fairly straightforward job. The water in lines have screw on connectors. The drain hose most likely has a clamp connector. Depending on the type of clamp you will need either a screwdriver or pliers. You can pick the hoses up at any hardware store.

You can take the hoses with you if you want to be certain of the size. Although I'm fairly sure they are standard.

Turn off the water at the valve box, remove the hoses -as Walt said possibly with slip joint pliers. 99% are direct hose thread replacement. Clean the filters in the washer hose fitting.