The combinations were a little bit confusing for me as well.
Common Kit - This is the base
Text OR Icon modifiers - You will need a minimum of one
The above 2, are basically the minimum.
In addition to the above 2, the others you may choose what appeals to you - eg: full size kb people may want the NUMPAD set; RGB set if you want to add color to the modifiers. So you add each subsequent 'set' by 'Add option' after choosing the base 2 sets.
Also, you may want to look around if you have any special needs. I think CM and Corsair need special size spacebars. I had to grab the 6u spacebar, as I (will be getting) a CM QF Pro. Geekhack.org is a good resource.
In addition to the above 2, the others you may choose what appeals to you - eg: full size kb people may want the NUMPAD set; RGB set if you want to add color to the modifiers. So you add each subsequent 'set' by 'Add option' after choosing the base 2 sets.
Also, you may want to look around if you have any special needs. I think CM and Corsair need special size spacebars. I had to grab the 6u spacebar, as I (will be getting) a CM QF Pro. Geekhack.org is a good resource.