You can start with this bash script for Aluminum to begin
Note: Make sure to fix two quantities while changing third one among INCAR,KPOINTS,POSCAR
for i in `seq -w 4.01 0.01 4.05` # change the range needed
cat <<EOF >POSCAR
Al bulk FCC
0 0.5 0.5
0.5 0 0.5
0.5 0.5 0
0.0 0.0 0.0
cp INCAR $i/
This is not a direct answer to your question, but instead the description of a resource that you can use to learn about high symmetry points and paths of any structure (including your orthorhombic lead halide perovskite).
Short description: it allows you to upload a crystal structure (in many formats, including QE, VASP, CASTEP, cif), and ...