If you don’t feel like taming one, then just use ForceTame. Or, if you can’t find one, then spawn one in using “SDF Titan 1 [For Tamed] 0 [For Wild]”

If you plan to tame one without cheats, the best way is to have a Quetzal with a Platform saddle, then equip a cannon on the back of it and make sure your loaded with cannon balls. Then start shooting it in the face until it’s knocked out. Then slap the saddle on it and boom. You have a sauropod version of Godzilla.