Well, you can always create global variables from Variables panel. Then there is a block for custom MQL code (the last one in the list). To use the variables, simply write their name where it's needed. Or, some calculations can be made directly in the input fields of all blocks... depending on how simple the calculation is. In all input fields you can write MQL code. Well, it's a little bit different for "string" inputs, but still MQL is possible.
