as you can see in the photo there is 2 cogs the bottom one is a locking cog and the upper one is the one to raise and lower your suspension.
You will need to undo the lower cog completely so it is no longer touching with upper cog from there u can adjust upper cog to raise or lower car.
Make sure both sides are adjusted the same i used a tape measure from a solid point on the car up to the bottom of the upper cog to get accurate height level on both sides.
I done this last night on my own car but yours don't look seized but a bit of WD40 will always help with turning the cogs freely

Be sure to make sure there is no dirt in the threads before attempting to move the cogs.