Kraken Authentication Api / how to set up signature

Hello.
Anyone tried to access Kraken through Wappler’s Api component?
I cannot understand how I must set up the signature to access.

Here are example data.

Schermata 2022-03-18 alle 13.04.26751×614 67 KB

Full example data are:
Private Key: kQH5HW/8p1uGOVjbgWA7FunAmGO8lsSUXNsu3eow76sz84Q18fWxnyRzBHCd3pd5nE9qa99HAZtuZuj6F1huXg==
Nonce 1616492376594
Payload nonce=1616492376594&ordertype=limit&pair=XBTUSD&price=37500&type=buy&volume=1.25
URI PAath: /0/private/AddOrder
API Sign: **4/dpxb3iT4tp/ZCVEwSnEsLxx0bqyhLpdfOpc6fn7OR8+UClSV5n9E6aSS8MPtnRfp32bAb0nmbRn6H8ndwLUQ== (should be the result)

Any advice ?

thank you
Roberto