First assess doors. Are they all the same width and height? Older interior doors will be anywhere from 24" to 32" wide and 6' 6" to 6' 8" tall. How tall will your paneling be? For this project, a 15' wall with 8' ceilings was paneled. Both 30" and 32" doors were cut down to a perfect 30" size and a large floor-level panel and crown trim made up the difference in height.
Remove and save* all door hardware. Mark each door 15" out from the center line and cut parallel to the adjacent panel. Check all doors for height. Flip doors upside down. Measure the distance from the upper panel to the top of the door (which would now be the bottom). Cut all doors down to the smallest dimension so that, once mounted, the panels will align perfectly.
Never throw away good hardware. Old interior door knobs have many possible repurposed uses such as towel rack knobs.
Mark studs across the wall at the floor and ceiling. Be sure to also mark out any wall plumbing and electrical outlets/wires. Decide what you will do with them in the layout before making cuts.
Mount 2x4 ledgers along with wall with 3" wood screws driven into studs. Be sure to level by chalk-lining the wall* or using a 4' level. Working from the center out, stand doors on this flat solid surface and secure them at tops and bottoms with 3" screws into studs.
It is common for floors and ceilings in older homes to be out of plane. Consider leveling ledger studs instead of measuring from the floor for a chalk line at each end of the wall.
After all the doors are mounted, the bottom panel can be cut. If you are using base molding, cut the bottom panel 1" short to alleviate any floor variance issues. Mount another row of 2x4s 1" from floor. Run a bead of construction adhesive along both rows of 2x4s. Install the lower panel with 15-gauge finish nails 6" on center, 1" from the top and bottom. Reinstall any wall baseboard to this lower panel. Next, mix up a can of automotive body filler and fill any large holes from removed door hardware*. While body filler hardens, mount the ceiling crown. The lower edge of the crown will overlap the top of the doors enough to cover the mounting screws. Next, cover the butt joints between the doors, lower panel and walls with 3/4" flat screen molding. This forms a batten strip that complements the paneling but also conceals and gaps.
Body filler is meant to cover small imperfections. When using it to fill larger holes, underfill the hole. The filler will shrink (and possibly crack) as it dries. Instead of fighting this at the finish layer, let it dry, then go over it with another thinner layer that is slightly proud from the wall. Once this second layer dries, sand flat to the wall.