Hello!
Ficus is easy to tie, as new sprouts are soft, I would recommend wiring just later, you can tie the branches you want to shape on the pot, and that won't scar it much as wiring...
To prune it is easy, when you remove the tip of a bud, the plant will direct it's growth to new buds, making new segments on the branches...
About aerial branches, I didn't get it...
To thicker their trunk you must pot it on a big portion of soil, like a mesh/net pot, or even a plastic stainer, so you can boost it's trunk and roots, and keep pruning it (cuz there will be a lot of buds)... As the roots grow out of the strainer you can lay it on the ground, so it can also feed from ground nutrients, once you think it's enough, it's easy to trim the roots outside of the strainer, and repot... But as you just get it, let this to a later maintance...