using wp_enqueue_script correctly

ok so yesterday I purchased a premium slider plugin and loaded it up and everything worked fine, then I went on to try to ‘properly’ insert my own js with the wp_enqueue_script method and although I got my own js to work, the slider has stopped working. I contacted the author of the premium slider plugin and he says I am not properly using wp_enqueue_script and that is what is causing the conflict. When i look on wordpress for the documentation and forums for the wp_enqueue_script I dont fully understand how to pull this off. (Newbie with developing with wordpress but knowledgable in the old school static way) so below is what I have in the following files. Obviously this is not correct so could someone provide me an example of what I would do for this? (I’m better with seeing actual code with notes), it is as follows:

In my functions.php

function my_bg_fade_script() {
	wp_enqueue_script(
		'jquery-fade',
		get_template_directory_uri() . '/js/jquery.fade.js',
		array('jquery')
	);
}
add_action('wp_enqueue_scripts', 'my_bg_fade_script');

function my_custom_bg_script() {
	wp_enqueue_script(
		'jquery-1-2-6-min',
		get_template_directory_uri() . '/js/jquery-1.2.6.min.js',
		array('jquery')
	);
}
add_action('wp_enqueue_scripts', 'my_custom_bg_script');

function my_custom_bg_script_2() {
	wp_enqueue_script(
		'jquery-bgpos',
		get_template_directory_uri() . '/js/jquery.bgpos.js',
		array('jquery')
	);
}
add_action('wp_enqueue_scripts', 'my_custom_bg_script_2');

Then in my header.php is:

<?php wp_enqueue_script("jquery"); ?>

	<?php wp_head(); ?>

I have been working with this for two days now and spent entirely too much time on it, any help you can provide will be MUCH appreciated! Thanks

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