The opponents open 2♦ multi, we must make a double that shows 12-14 points and balanced (with a 5 card major just keep it simple and bid the major rather than double), don't worry about your shape, you don't need both majors to double a multi. Do NOT pass with an opening hand or else it will lead to uncomfortable auctions and bad results.
The most important signals
Double or bid?
Bid as high as possible!
Defending against a multi 2♦
Transfer or not?
Nv compete
How strong vulnerable?
Preempt suit quality
6322 and 7222
2♣ opening
Doubleton lead
Passive lead
When to lead active
1N with 5422
Takeout double
Negative double
Splinters
Competing partscore
Try not double
Ace Ace King
2 level overcall
Lead Trumps #1
Lead Trumps #2
7 card GOOD suit
To open or not, pre-empt or not
Let the opponents play when they are misfitting
The strongest hand
Be practical
Losing trick count bidding
Favourable vulnerability
Be a nuisance
Big trump fits
What does 3♥ show?
Mental game
6+ card suits
Use puppet stayman more
Don't push slam in competition
The unusual 2♠ bid
Intermediate jumps
Conventions
Choice of equal cards
Don't false card
Never preempt with 11 points
Is the bid forcing?
Double, Double
Double 1NT, next double
Counting Habit #1
Opener rebidding bad suits
Responder bidding bad suits
2♦ opening
Don't split honors