gauge prob and want to keep stock

my roommate got his dad truck after he passed but as we checked it to see if any thing was wrong we seen oil temp and gas gauge didn't not work any idea on how to fix this when we turn the truck on they just max out well oil and temp and volt due gas just don't move im not good with the new motor but this i thought wold be ez fix but i was wrong

The are way to many ways that this could be wrong. It sounds to me that the circuit board on the guage cluster is bad. If it is good start replacing sending units for each guage.