The last option you have is by hovering your mouse over the gun in your action bar at the bottom of the screen, right clicking and changing the gun to “ Melee Mode” and then pressing the “ Left Mouse Button” which should now do a melee or stabbing animation instead of firing the gun. The next possible key bind would be the “ M” key which is also bound to the map in Project Zomboid so if this is the case I would definitely change this key binding in the options of the mod.

You could approach the zombie again and try pressing the “ Home” key on your keyboard, which a few players online said works for them. The keys you should check before rebinding vary. If this doesn’t work the action could be bound to different keys in the mod pack. You can either get within melee distance of the zombie and press “ Spacebar” and your character should use his bayonet instead of pushing the zombie away. There are a few different possible ways to use the bayonet. If you have a compatible attachment in this case, a bayonet, you should be able to attach the bayonet to the end of your firearm just like that! Bayonets can be a tricky attachment to learn how to use but once you learn them you will want them on each of your guns! To attach a bayonet you would first attach it to your gun just like any other attachment by right clicking your equipped fire arm and selecting the option to “ Attach Bayonet“. There are many mods out there for Project Zomboid but one of the most popular mods is Brita’s Weapon Pack which adds tons of new fire arms and attachments for them including bayonets. Project Zomboid How To Use Bayonets in Project Zomboid:

Free download britas weapon pack