To make a capture attempt, you must be engaged with your target, whether fighting them, chasing them, etc. You must then make a post that details how you are attempting to make the capture, such as knock out, snare in a net, grab, etc. You will then immediately use the dice roller and roll a 10 sided die. If it is odd, the capture is a success; if it is even, the capture is foiled. The process is the same for the defending side attempting to capture attackers.
Being engaged with a person requires actually posting on their specific pull-down for at least two posts, followed by a post actually addressed to the target, such as chasing them, trying to corner them, etc. All proper role play should be taken in getting to their pull-down as well.
Raider going from the gates in one post to being in the 'Great Hall' making a capture attempt in the next post is not acceptable.
Post 1: Raider breaks through the gate.
Post 2: Raider runs along the street.
Post 3: Raider finds & enters the Great Hall.
Post 4: Raider starts searching through the Great Hall for valuables.
Post 5: Addressed to Lady Pan Wielder that you've spotted her and begin chasing her.
Post 6: Capture attempt by trying to grab her from behind.
If you make an attempt to capture Lady Pan Wielder but fail, you are not permitted to attempt to capture her again for the remainder of that raid.