How to combine files and set conditional text and color in result excel file using vba?

I have two excel files, source and result. They both have more than one sheet, however, only the one which opens when the file is double-clicked is important (but would be great to somehow tell the vba how the sheet to be used is named, so that I do not have to delete the other sheets in the worksheet in order to get the vba running). Result file already exists, however column action in the result file in the attachment is filled to help explain how the calculated result should look like. This would be empty. But the other columns are existing already. I want to create a VBA excel file, which I put into the same folder as the source and the result file. The VBA file should run when I click on generate and fill the action column according to specific rules: 1.) The main point: fill in the action column in the result file, depending on the number column in the source file for each specific ID (so the calculation needs to be done for matching IDs). - if the number is empty then fill in the number column in the source file with "Text B" and background-color to be read in from given user entries. - if number is smaller than threshold 1 (but not empty, 0 is also accepted as a valid number) leave the field in the action column empty - if number is larger to the threshold 1, put into "Text A" with background-color to be read in from given user entries - if the column variable b in the result file has a certain background color (to be read in) with text "ACTION NOT NEEDED", then the action column should be filled with the text "action needed?" with red background color, regardless of the number in the source file - if the column variable b in the result file has a certain background color (to be read in) without text "ACTION NOT NEEDED", then the action column should be filled just with red background color (also regardless of the number in the source file) - if the column variable b in the result file has a certain background color (to be read in) regardless what text is in), then the action column should be filled just with blue background color (also regardless of the number in the source file) - if the column variable a in the result file has certain background color (to be read in) (regardless what text is in), then the action column should be filled with text "more info needed" (also regardless of the number in the source file) - special case is if the category variable in the source file shows "F": - if the number is smaller than the threshold 1 (but not empty, 0 is also accepted as a valid number) then the action field should be empty - if the number is larger than the threshold 1 the action column in the result file should be filled with text "decision pending" - if no number is given (so the number field is empty), then it needs to be filled with "Text B" and yellow background-color I want to "read in" the background colors (not give specific RGB or so). The specification where the number column is and where the action column should be filled is explicitly given by the user, same for variable a and b column. (As the source and result files are quite large, this can be also something like "BX" or so, here for simplicity its F, E, C, and D). When generate is clicked, the code should create a file Result_filled which is the result file with the filled action column. 2.) Second point: check matching ids and names (to be placed in additional sheet). 1.) if there is an ID which is in the source file, but not in result file 2.) if there is an ID which is in the result file, but not in source file 3.) if there is a mismatch between names and if yes identification key should be given and name from source and name from result (to see differences). ID column is split into two columns, needs to be joined to give an unique ID. And ID numbers are given in text format. Names of the id columns should be read-in fields. Check attachments.