In Combat Arena on Roblox, attachments are usually earned by playing matches, leveling up, or unlocking them through the game’s weapon/customization system, then equipping them from your inventory or loadout menu. The exact steps can vary by update, so the safest path is to check the weapon edit/customize screen after you unlock a gun or attachment slot.

What to try

  • Open your inventory/loadout and look for a modify , customize , or attachments option on the weapon.
  • Play more matches to see whether attachments unlock from progression or a secondary update style system.
  • If the game uses weapon builds, try equipping attachments from the gun’s edit screen rather than expecting them to appear automatically.

If it is not working

  • Make sure the weapon actually supports attachments in that mode or version of the game.
  • Check whether the attachment must be unlocked first through rank, currency, or a quest.
  • Restart the game after an update in case the UI changed.

Quick note

Some search results point to similar Roblox gun games where attachments are added through a modify menu or by spawning a weapon with attachments already included, but that may not match Combat Arena exactly.

TL;DR: open the weapon customize menu, look for attachment slots, and unlock/equip them from there after leveling or earning them in matches.