Some times IDA's decompiler translates more than variables into a single variable or an array of varibles, for example, I have 2 variables
A a; // size = 30h
B b; // size = 60h
but IDA gives
A arr[3];
how can I split them out?
You can redefine the type of the variable by right clicking on its name anywhere in the function and selecting "Set lvar type", or by pressing the Y
key. Afterwards, IDA will automatically create new variables that will fill in the remaining stack space, you can also redefine their type if needed.