If it has drum brakes on that axle, you need to remove the drum. Depending on whether the brake shoes are behaving this can be fun (or not). If the drums have become lipped you may get away with slackening the drum brake adjusters to create enough clearance to get the lipped drum over the shoes. If not then brute force and ignorance will often work but there is likely to be collateral damage. The worst case scenario is to have to shatter the cast drum. Wear eye protection.

If it has discs, most discs are held onto a hub by a small set-screw or two and the lugs (or studs as we call them in the UK) pass through flanges on the hubs, then the discs, then the wheels and then the wheelnuts hold the lot together. To get the studs out to replace the broken one involves removing the hub - and that will depend on the sort of wheelbearing. Some are held together by a castellated nut that sets the bearing clearance. With luck the bearing runs in a cage and does not fall to pieces when you undo the nut (after removing the split pin through the castellations). Some have use-once nuts and you bend the nut end to secure the bearing.   Some have non-dismantleable bearings that are pressed into the hub or pressed onto the axle. Whatever you've got I've never seen one that does not involve removing the hub and therefore the bearing. For the last type you will need at least a bearing puller to remove and probably a hydraulic press to reassemble.