You should have at least been shown how to refuel, correctly and safely, during your training......
Not an option at many airfields, in fact at some fields it will only be a limited number of employees who are insured, but if you are at a field where this is required and you are not happy to do it yourself then ask and generally there will be someone on hand to assist.
For requesting start I have never bothered a ANY airfield unless I am on an IFR plan!