How does it work?
The multiplier bonus means that you are getting an extra value to your possible win. This bonus is awarded if your bet meets the following simple criteria;

Your bet has more than 5 or more selections
The 5 selections must have odds of at least 1.30. For example, if your ticket contains 12 selections with 8 having odds of 1.10, 4 having odds of 1.30, then the bonus will not be applied. But if your ticket has selections with 8 having odds of 1.30 and 4 having odds of 1.00, then the bonus will apply on the 8 selections. The bonus starts from 5% of the possible winning (for 5 events) and increases by an average of 5% as you add more events to your ticket. If your ticket has 40 selections matching the criteria, then your bonus is 225% If your ticket is a winning ticket, then you will get your possible win + the bonus, for example, if you win 1,000,000 you will get (1,000,000+ 225%*1,000,000) = (1,000,000+ 2,250,000) = 3,250,000

The Bonus Calculation can be seen below; Total Odds * Stake = Possible Winning

ACCUMULATOR BONUS RULES
5 Events 5% Bonus Accumulator
6 Events 10% Bonus Accumulator
7 Events 15% Bonus Accumulator
8 Events 20% Bonus Accumulator
9 Events 25% Bonus Accumulator
10 Events 30% Bonus Accumulator
11 Events 35% Bonus Accumulator
12 Events 40% Bonus Accumulator
13 Events 45% Bonus Accumulator
14 Events 50% Bonus Accumulator
15 Events 55% Bonus Accumulator
16 Events 60% Bonus Accumulator
17 Events 65% Bonus Accumulator
18 Events 70% Bonus Accumulator
19 Events 75% Bonus Accumulator
20 Events 80% Bonus Accumulator
21 Events 85% Bonus Accumulator
22 Events 90% Bonus Accumulator
23 Events 95% Bonus Accumulator
24 Events 100% Bonus Accumulator
25 Events 105% Bonus Accumulator
26 Events 110% Bonus Accumulator
27 Events 115% Bonus Accumulator
28 Events 120% Bonus Accumulator
29 Events 125% Bonus Accumulator
30 Events 130% Bonus Accumulator
31 Events 135% Bonus Accumulator
32 Events 145% Bonus Accumulator
33 Events 155% Bonus Accumulator
34 Events 165% Bonus Accumulator
35 Events 175% Bonus Accumulator
36 Events 185% Bonus Accumulator
37 Events 195% Bonus Accumulator
38 Events 205% Bonus Accumulator
39 Events 215% Bonus Accumulator
40 Events 225% Bonus Accumulator
Things to Remember; Void events are not considered as a qualifying selection