Installing T-posts to support wire fencing is relatively low cost, and they are easy to install. For a solid fence line, you will need to have wooden fence posts wherever there are corners and for bracing at the corners. For details on installing wooden fence posts, see How to Set Fence Posts in Gravel and Concrete. For right now, we will just deal with actually installing T-posts.
Once you have the corners set and braced, run a guide line between them to ensure you set your T-posts in a straight line. You should space your posts 8-12 feet apart as a general rule, although 10-12 feet apart is sufficient for 5-6 wire barbed fence.
Position each post with the anchor plate at the bottom and perpendicular to the fence line. Studs should face either inward or outward depending on whether it's more important to keep livestock in or predators out. If animals will be putting more pressure against the inside of the fence, face the studs inward. If animals will be putting more pressure from the outside of the fence, face the studs outward.
Drive the posts into the ground 18-24 inches, completely burying the anchor, in order to avoid the possibility of your animals pulling the post out of the ground. As you move along the fence line during the installation process, make sure you check back to ensure your line stays straight.
Finally, as you are stringing the wire along the fence posts, make sure you attach it securely to the studs so that it doesn't move up and down and can't be pulled away from the posts.