We don’t officially support the MR headsets yet, as there are still some bugs (like the tool tips during the tutorial not showing up properly, also the fishing uses the controller rumble to indicate a fish on that doesnt seem to work with MR headsets), but Ill post some step by step instructions on how to complete the tutorial so you can progress through the story, as these are the only 2 bugs im aware of with using the MR headsets in Orbus.
When you first talk to Bart and his dialogue ends, reach behind your head to unsheathe your sword with the grip button (there is an area directly behind your head that you press the grip button). This will progress the tutorial an should appear another section of text and the practice dummy you need to defeat. Once the first dummy is defeated go back to Bart and wave at him again and read the next text dialogue. He will then want you to go to the arena behind you and defeat a Redtail (monster), be sure to block with your shield when the monster attacks (in your left hand sheathed behind your head) and attack with your shield out of the way, once killed return to Bart and wave again. He will then give you dialogue then want you to press the menu button to open your inventory, then holding the trigger button (to make your finger point) select the backpack (player inventory) and select the bow from the right side by pressing it with a pointed finger, and moving it to the weapons slot on the left screen (putting it in your right hand) . Then move the bow from your right hand to your left hand (if you are left handed you still need to move the bow over, but may switch it back if needed). Then press the “X” button in the center screen to close the player menu. This will progress the tutorial and there should be a line of text then the dummy will appear next to the tree. Defeat the dummy and return to Bart. and wave again to start the dialogue. He will then have some text and once its over open your inventory again (pressing the menu button) and select the backpack. Place the musket (gun on right hand screen) where your bow is on the left hand screen. Press the “X” to close the player menu and there will be a line of dialogue and the dummy will appear near the tree again. defeat the dummy with the musket and return to bart, He then talks about harvesting plants, and wants you to grab your harvester (the pick axe on your belt, using the grip button) this will spawn in 3 queens ear in the middle of the arena where you killed the redtail. Harvest the queens ear by swining the pickaxe at the base of the plant, once all 3 are harvested return to bart and wave again. He will then explain your compass (located on your left shoulder) and want you to grab it (using the grip button) , then he will want you to turn it over(like dumping out a cup of water) which will spawn in your player journal. Once out you need to turn the page (using the grip button at the lower right hand corner) and read some of the additional tips in the journal. Once done use the grip button and grab the journal in the middle of the spline and place it behind your head (like sheathing a weapon) to put the journal away. he will then send you to kill a King Stag (This is the first time you need to leave the training area during the tutorial). head down the steps and head left through town to find the king stag and kill it, once dead gather the stag meat (loot bag on ground, gather by using grip button and placing behind your head like sheathing a weapon) and return to bart. This is the end of the tutorial, and he will send you to see chef letharow which will begin the main story quest for you.
Hope this helps if you run into any more snags let me know.