I have seen two thoughts.
Roof sheathing peak.
Then align a chalk line.
Start the sheathing at the eaves and work your way up to 1 inch from the peak.
It must be completed at the very end of the shingle run to overlap the uppermost shingles and form a weatherproof.
For safety temporarily nail a 2 x 4 toe board horizontally across the lower panel of sheathing to brace yourself against as you add the second and subsequent courses of sheathing.
How should the sheathing meet at the roof peak when there will be no ridge vent.
Preparing the peak capping a roof is the last thing done during a roofing project.
This is a simple pitched roof line with ridge beam and rafters attached with slope hangers.
Install sheathing perpendicular to roof trusses one slope at a time.
Nails size 8b should be installed every 6 inches on edges and every 12 inches in the center area.
Check for alignment and end support as you go.
Snap a chalk line along the overhanging sheets along each side of the roof aligned with the edge of the last rafter and trim off the excess sheathing with a circular saw.