Where does this tube next to 12V go?

Hey, I just replaced my 12V with OEM TrueStart AGM and the car starts, hurray. This tube doesn’t seem to plug into anywhere. I believe I’m also missing a piece of plastic down here because my “floor” next to the battery looks different from Nutzaboutbolts’s. So I don’t have that hole that his tube is plugged into. I have attached a screenshot from his video and a picture of my 12V.

I believe the previous 12v (3rd party now ~7 years old) also left this tube around when my dad changed it, but he doesn’t remember.

Should I plug this into anywhere? Or am I good to go? Thanks in advance

edit: Actually I believe where I currently put the bar covering the battery is where the tube should go, but I’m not sure if the bar screw can go down to that second hole. Will try.

 

It seems I don’t have the hole where the tube goes, and I don’t have the hole the brace is supposed to screw into. See pic

edit: added another screenshot from the video. Mine doesn’t look like that for sure. I think I need that piece of floor to get that hole where the brace should go.

 

To clarify: the brace is hanging in space right now. There is air below the screw, I didn’t screw it into anything.
I tried pushing the tube plug into that hole, and the plug is too big for it. The tube doesn’t reach that second hole to the right.

 

I will check for the hole at the bottom later.

I’m not sure what else there is to try again. The new OEM battery fits in the tray, clamps stay on, the brace goes where it has been previously. I know the brace should go somewhere else but I don’t have that place. I think at some point my dad took out the “flooring” (?) there for some purpose and didn’t put it back, then connected the brace like that anyway. He doesn’t remember anymore though.