When your hub is in 'edit' position, on the right hand side , at the bottom you can view, ' organise your content' option. You can move the capsules to place your photos, text, poll, video etc. Wherever you want them to be, you can also move the arrow to expand or reduce the size of the text or photos. Hubtool video also can guide you. Hope that helps!
You can enter a capsule at any point in the hub from the left side, just holding your cursor near the left edge, in between capsules. Then you can move it up or down with the arrows on the capsule itself, or in the "organize your content" section on the right. Hope this makes sense.