Search:

Are you using tape?
What other stones do you have available to you?
Is this the first razor you have honed?

"Does this mean I have to put pressure with my finger in the middle of the spine as I...

Yes, but as said, in you case, your bevel is not fully set. Looking at your razor photo enlarged, one can clearly see the bevel is not fully set or at least you are not honing to the edge at the heel...