So for this specific code I have 3 dropdowns and 1 button? —> CORRECT!
It depends if you do use → dynamic-pages?
It depends also on the structure of your database (collection).
Do you use a database, where you store allt the informations?
You will have to create a DATABASE first, to use this method!
DATABASE-EXAMPLE (based on your message)…
So after a cascading dropdown, a specific button will show up, connected to a PDF file or an image.
So if the client choose he wants a women's shirt size M, a button with "Size M Template" will show up, and if a client choose a man's shirt size XL, a button with "Size XL Template" will show up.
Those buttons must be connected to different files, so exactly what the client choose will appear on the exact button.
Your virtual-database…
–title -------- type ---- size -------- file-url --------
shirt-1 — woman — S — https://file-URL-1
shirt-2 ----- man ----- S — https://file-URL-2
shirt-3 — woman — S — https://file-URL-3
shirt-4 — woman — S — https://file-URL-4
shirt-5 ----- man ----- S — https://file-URL-5
shirt-6 — woman — S — https://file-URL-6
shirt-7 ----- man ------ S — https://file-URL-7
- Connecting your DATASET to the created (new) DATABASE.
- Entering the ID of your new DATASET (“dataset1” for example) into the code…
var myDataset ="PlaceHereTheIDofYourDataset"
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Creating 3x Dropdowns on the page (attention on the ID !!! )
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Creating 1x Button on your page (attention on the ID !!! )
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Inputting the code to the current page (first activate Dev-Mode).
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Searching for Dev-Mode-Info here in the forum, if do not know what it is
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Now taking some time and try to understand all the steps first.
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Try to solve the rest on your own
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Send me a —>
if you need more help 
Good luck and happy coding.