What happens next in this paragraph?

How to build a deck railing
Count how many posts you will need.
Your deck might already be supported by posts, especially if it is covered. If not, you'll need to install these so that there will be something to support the railings.
OPTIONS: (a). The taller your deck is, the more posts you'll need to install. You can prepare the posts according to your deck width and height. (b). Plan to evenly space posts around the perimeter of your deck, such as every 6 feet (1.8 m). Keep in mind that some posts may be larger if they're going to have a gate attached or support stair handrails. (c). Estimate how many posts you will need and number them according to the size of your deck. You can also write down your estimated size of posts from this example. (d). Learn to measure your railing's length. You may want to first measure the width of your deck to see how much overhang there will be around it.
(b).