You may be able to do this with a pop-up, but anything larger requires the trailer be as close to level (side to side) before ever unhitching. This mean putting something under the tires to raise the low side.
Once finding the exact position you want the trailer sitting, you mark that spot where the tires sit. Then pull forward or backward, put something in that spot, like boards or Lynx blocks, and then pull the camper on them, raising the low side. Chock the tires (always). Then unhitch (only after chocking the tires). After you unhitch, then you level front to back with the tongue jack, then lower your stabilizer jacks snug.
Unless you have built in hydraulic levelers on your camper that are capable of actually lifting the whole thing, the rest of us depend upon raising the low side by rolling the tires up on something.
When we had a pop-up, I always leveled by putting lumber under the tires first, then front to back with the tongue jack; never leveled using the stabilizer jacks.
To each their own though!