The path for data files can be added directly to the sequencer.
First an additional sequencer ''Text'' variable has to be added in the settings tab of the sequencer (a solution on how to choose custom data file name can be found here).
A custom path can be chosen with the Form block. To input the chosen data path it is necessary to assign it to the sequencer variable which was added ('Path'). The input control must be chosen and a variable name must be added to the settings.
For the open folder dialog option we have to open the Form parameters (in the new window) where we have to check the ''Open folder dialog button'' box.
With these settings the pop up window is changed and a new button is added where it's possible to search for chosen path.
The 'Path' variable is now set, it only needs to be combined with the "File name" in calculation block in the following way. The order of the variables and the additional backslash (Alt Gr + Q) is important for the formula to work properly.
It is also important not to forget to add the 'File name' variable to the Start Storing block.