Youll want to keep them separate until theyre both neutered since theyve stated fighting. Itll only be a matter of time until they fight inside of their shared hutch. Find a way to separate them until a month after they are both neutered, then start the bonding process
To bond, start in a neutral territory. Put them right next to each other and pet them. After several minutes, put them back in their nonshared cages/hutches. Do this about once an hour until they dont seem stressed out,t hen watch them for abour an hour at a time in the neuteral territory, always putting them back into their own cages afterwards. When thats fine, leave them there for 2 hours. Then 3. ect
After theyre fine in the neuteral territory, bring them to the hutch they will share. Again, put them in together and pet them for several minutes then into their own cages/hutches they go. Do this a few times before leaving them in there for an hour+ together. Once theyre fine (no signs of aggression), move them to the place they used to fight. Start the same way, short petting sessions until theyre calm, then longer sessions. Break up any fights and always end them on a positive note. Keep putting them back into their own separate cages. While you are around and they are within eyesight and hearing range, you can put them in the shared hutch, but i wouldnt leave them in there while you arnt nearby, yet
Once they arnt fighting in the place they used to fight, allow them full access to the patio and their shared hutches. I still wouldnt leave them alone over night, yet. Give it a few sessions with no fights before thinking about leaving them over night together
Good luck!