Save concatenated array to collection

Hi Doron,
Thanks for helping out. The code below is what I have now, after the corrections you pointed out. The setFieldValue, as I understand it from the link you refer to, needs to FieldName, not the FieldKey, therefore I changed it to match what I have in the collection.

import wixData from 'wix-data';
var selections = [];
for (var i = 0; i < selections.length; i++) {
	selections[i] = '';
}

$w.onReady(function () {
	//TODO: write your page related code here...
});

function update_checkbox(checkboxID, string, ID) {
	if ($w(checkboxID).checked) {
		selections[ID] = string;
		console.log(selections);
	} else {
		selections[ID] = '';
		console.log(selections);
	}
}

export function submitstrategies_click(event, $w) {
	$w("#strategiespanel").expand();
	$w("#strategiespanel").show("FadeIn");
}
export function closestrategies_click(event, $w) {
	$w("#strategiespanel").collapse();
	$w("#strategiespanel").hide("FadeOut");
}
export function closetools_click(event, $w) {
	$w("#toolspanel").collapse();
	$w("#toolspanel").hide("FadeOut");
}
export function submittools_click(event, $w) {
	$w("#toolspanel").expand();
	$w("#toolspanel").show("FadeIn");
}

export function checkbox1_change(event, $w) {
	update_checkbox('#checkbox1', 'Autocad', 1);
}
//many functions, one for each checkbox...
//...
export function checkbox45_change(event, $w) {
	update_checkbox('#checkbox45', 'geothermal heating', 45);
}

export function button6_click(event, $w) {
	$w("#ifc_data").onReady(() => {
		var tools = '';
		var strategies = '';
		for (var t = 0; t < 14; t++) {
			tools += selections[t];
		}
		for (var s = 15; s < 44; s++) {
			strategies += selections[s];
		}
		$w("#ifc_data").setFieldValue('digital tools', tools);
		$w("#ifc_data").setFieldValue('strategies', strategies);
	});
}

The errors are:
TypeError: $w(…).onReady is not a functionsubmit - Line 191
//this is the line in the button6_click function

save operation failed: DatasetError: Some of the elements validation failed
//I assume this has something to do with the $w(“#ifc_data”).onReady(() => {…

Can you assist me with this further?

Thank you