I was learning in a sefer which discusses a case where they couldn't do hagbah, and the Mechaber suggested to do the hagbah like the Teimanim which is to leave it on table in some way, but I didn't fully grasp how it's done. Is there a picture of their technique or a description how it's done?
Using some cloth (Talith or similar) the parchment is lifted to about head-height. To do this, one would have to unroll the Sefer Torah while lifting it.
Probably best to grab it at the seam (which you can find every 3 to 4 columns).
After the Hagba is over, one would have to roll back the slack while slowly lowering it.