mame32 memory card question help

hello this had me really confused and i did not know where else to ask this kind of question

ok so i have mame32 as you already know and i'm playing a game called "Savage Reign" its a fighting game and recently i found a cheat that says the following :

"A memory card is required to unlock King Leo. In order to do so, the memory card must contain a file with all characters having beaten him at least once. Start a 2-player game and highlight King Lion and press Down 10 times followed by the A button. A flash will confirm whether you correctly inputted the code or not and if done right, the picture will show Leo instead"

ok so how do i actually do this so i created a memory card and loaded one and now what do i do ?

do i just have to play the game and beat it with all 10 characters while the mem card is loaded ? also can i use more coins or do i have to beat it with one coin only per character ???

and also when i beat the game with 1 character how do i save it to the mem card when i want to exit the game ?

i never done this before never used a mem card so if someone knows pls answer

also i hope im not breaking any rules by asking this here or about cheats :)