Here's a screenshot of the flow from my very old tutorial.
And here's the code you can import and adapt.
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// Set this to what you want to pass on\n }\n else if (state == \"on\") {\n state = \"off\";\n node.status({fill:\"red\",shape:\"dot\",text:\"Button_2 is OFF\"});\n msg.payload = 0; // Set this to what you want to pass on\n }\n flow.set(\"button_2\",state);\n return msg;\n}\n\nelse if (msg.payload == \"reset\") {\n flow.set(\"button_2\",\"off\");\n node.status({fill:\"red\",shape:\"dot\",text:\"Button_2 is OFF\"});\n msg.payload = 0; // Set this to what you want to pass on\n return msg;\n}\n","outputs":1,"timeout":"","noerr":0,"initialize":"","finalize":"","libs":[],"x":350,"y":460,"wires":[["535a5daa5fc83194"]]},{"id":"535a5daa5fc83194","type":"debug","z":"1774ba78f53ce4da","name":"","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"false","x":530,"y":460,"wires":[]},{"id":"be8d2b42fbbb6108","type":"link out","z":"1774ba78f53ce4da","name":"initial_reset","links":["be5faf56e2a51ab3","fa363fb466604d9b","704d1a01235a86a4","1efa68ecc6533533"],"x":615,"y":140,"wires":[]},{"id":"be5faf56e2a51ab3","type":"link in","z":"1774ba78f53ce4da","name":"","links":["be8d2b42fbbb6108"],"x":175,"y":300,"wires":[["c2e6b3e851c7a717"]]},{"id":"fa363fb466604d9b","type":"link in","z":"1774ba78f53ce4da","name":"","links":["be8d2b42fbbb6108"],"x":175,"y":500,"wires":[["04d6ffdcd9087a2a"]]},{"id":"26284ccd7a95b13e","type":"inject","z":"1774ba78f53ce4da","name":"Count on Button_3","repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"increment","payloadType":"str","x":150,"y":600,"wires":[["9c9c576e8024bb83"]]},{"id":"9c9c576e8024bb83","type":"function","z":"1774ba78f53ce4da","name":"C","func":"if (msg.payload == \"increment\") {\n var counter = flow.get(\"counter\") || 0;\n counter = counter + 1;\n node.status({text:\"Counter = \"+counter});\n flow.set(\"counter\",counter);\n msg.payload = counter;\n return msg;\n}\n\nelse if (msg.payload == \"reset\") {\n flow.set(\"counter\",0);\n node.status({text:\"Counter = 0\"});\n msg.payload = 0;\n return msg;\n}\n","outputs":1,"noerr":0,"x":350,"y":640,"wires":[["5b9a826c09caca52"]]},{"id":"5b9a826c09caca52","type":"debug","z":"1774ba78f53ce4da","name":"","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"false","x":530,"y":600,"wires":[]},{"id":"704d1a01235a86a4","type":"link in","z":"1774ba78f53ce4da","name":"","links":["be8d2b42fbbb6108"],"x":175,"y":640,"wires":[["9c9c576e8024bb83"]]},{"id":"08e0b002d4f126f4","type":"inject","z":"1774ba78f53ce4da","name":"Reset the counter","repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"reset","payloadType":"str","x":150,"y":680,"wires":[["9c9c576e8024bb83"]]},{"id":"4e4ee4b89a45f5b2","type":"ui_button","z":"1774ba78f53ce4da","name":"On","group":"4bfa11d8.376b98","order":1,"width":"3","height":"1","passthru":false,"label":"On","tooltip":"","color":"","bgcolor":"","icon":"","payload":"on","payloadType":"str","topic":"","x":870,"y":280,"wires":[["21dcf5bd9ce91ab1"]]},{"id":"ff4300fcc0e323a7","type":"ui_button","z":"1774ba78f53ce4da","name":"","group":"4bfa11d8.376b98","order":2,"width":"3","height":"1","passthru":false,"label":"Off","tooltip":"","color":"","bgcolor":"","icon":"","payload":"off","payloadType":"str","topic":"Off","x":870,"y":360,"wires":[["21dcf5bd9ce91ab1"]]},{"id":"20aa8df75ef15247","type":"ui_text","z":"1774ba78f53ce4da","group":"4bfa11d8.376b98","order":3,"width":"6","height":"1","name":"Button status","label":"Status: ","format":"{{msg.payload}}","layout":"row-center","x":1220,"y":320,"wires":[]},{"id":"21dcf5bd9ce91ab1","type":"function","z":"1774ba78f53ce4da","name":"E","func":"if ( (msg.payload == \"off\") || (msg.payload == \"reset\") ) {\n flow.set(\"button_3\",\"off\");\n node.status({fill:\"red\",shape:\"dot\",text:\"Button_3 is OFF\"});\n \n msg.payload = \"Button_3 is OFF\"; // Set this to what you want to pass on\n return msg;\n}\nelse if (msg.payload == \"on\") {\n flow.set(\"button_3\",\"on\");\n node.status({fill:\"green\",shape:\"dot\",text:\"Button_3 is ON\"});\n \n msg.payload = \"Button_3 is ON\"; // Set this to what you want to pass on\n return msg;\n}\n","outputs":1,"noerr":0,"x":1030,"y":320,"wires":[["20aa8df75ef15247"]]},{"id":"1efa68ecc6533533","type":"link in","z":"1774ba78f53ce4da","name":"","links":["be8d2b42fbbb6108"],"x":895,"y":320,"wires":[["21dcf5bd9ce91ab1"]]},{"id":"4bfa11d8.376b98","type":"ui_group","name":"on-off-demo","tab":"1f158e7d.631e42","order":1,"disp":true,"width":"6","collapse":false},{"id":"1f158e7d.631e42","type":"ui_tab","name":"Button demo","icon":"dashboard","order":4,"disabled":false,"hidden":false}]
