Obvious place to start was the Entrance Hall, maybe the Courtyard. Entrance Hall was where their stuff got delivered initially though right? West walked in and saw immediately, with great relief, that their trunks were there. And every single one labeled Slytherin. Were they the only ones then??

West had to find his trunk. For reasons.

The next priority after that was Theo's, obviously.

...
....

....

"Accio trunk!" He said forcefully, focusing on his own trunk.

This proved to be ill-advised, given his trunk was on the bottom of the stack and dislodged itself in a rush, violently bursting through and knocking other trunks over.

West had to DODGE and somehow found himself on his back on the ground, still gripping his wand, and with his trunk hovering politely and looking none the worse for wear a short distance from his elbow. Well. That was... a start. He got up and eyed the pile. Maybe 'Accio Theo's trunk' wasn't a good idea either. Manual looking then. Sigh. The things he did for friendship, honestly.