If you don't have the confidence or knowledge to clip them I don't recommend it, just file if you can. With friendly birds you can turn it into a game, my galah has started letting me play with his feet so I plan to desensitize him to a nail file so hopefully I never have to restrain him and clip nails (not that'd I'd ever clip his nails by myself).
You want the ones that are smooth on the top rough on the sides, so their feet are not on an abrasive surface. They also have to be positioned in a spot where your bird is active e.g. in front of a food or water bowl. They're useless if you bird just sits on them.