If you want it to be buffed you can use notepad ++ ( you can use notepad aswell i think not sure ) For this Tutorial
STEPS

STEP 1
Download the Mod ( Obviously )
STEP 2
Make sure it is downloaded so get too many items or something and use it on a rog non shipwrecked Compatible world
STEP 3
Go into your steam folder ( if you have a shortcut of steam you can right click it and then open folder or something otherwise search for it in your C: , Programs Folder ) Then go into SteamApps Then Common Then dont_starve from here go into the mods folder
STEP 4
When you are in the mods folder you will need to search up this in that folder ( or just find it ) 236777787 once you search this up a folder will pop up click it
STEP 5
Now You will see some files you are looking for these two files modinfo.lua and modmain.lua
STEP 6 ( Optional )
You want to use this in shipwrecked? You don't care that it COULD crash the game? ( This mod shouldnt so you should be fine ) Then open up modinfo.lua and add this in under ROG compatible or whatever shipwrecked_compatible = true safe it and you are done
STEP 7
Open up modmain.lua and now this is really really easy There are two things at the top TUNING.GOLDENSPEAR_USES = 300
and
TUNING.GOLDENSPEAR_DAMAGE = 36
if you want it buffed change the second one to whatever i suggest 38 as that would be weaker than the battlespear but stronger than the normal one by quite a bit. The first one as it says is how much uses it has you can buff this if you want.
STEP 8
CONGRATULATIONS YOU HAVE FINISHED BUFFING THE SPEAR!!
now go play don't starve.