The ballot for Wimbledon tickets for British Tennis members (11 years+) is open - you have till 22nd February to opt-in and have a chance of being allocated tickets. See https://www.lta.org.uk/major-tennis-events/grand-slams/wimbledon/ballots/btm-ballots-home/ for more details.
The more members that opt in, the more tickets which are assigne d to the club - a ballot is help within the club around those who opted in to distribute the tickets. In recent years the club has received lots of tickets for later stages on the show courts - an excellent day out!
If you are already a British tennis member (BTM) this is a fairly straight forward process: just login via https://www.lta.org.uk/member/login/ and then just look for the opt in button.
If you are not a British Tennis member, then its free to signup up at https://www.lta.org.uk/member. Remember to select Longniddry Tennis Club as your club.