Two sidebars for a noob

Hello everyone!
I’m a total noob to wordpress theme development so go easy on me. ??
I’m trying to develop a theme with two sidebars, I have a picture of the layout I want, on my blog Tech Strive. I followed a tutorial which I learnt a lot from but I don’t know how to code for two sidebars.

I have no clue what the functions.php file is supposed to look like for two sidebars, and that’s the part I need the most help with (it’s totally blank).

I named the sidebar files sidebar-left.php and sidebar-right.php. I think all the code is right except for the following

<div class="sidebar-left">
    <ul>
    <?php if ( function_exists('dynamic_sidebar') && dynamic_sidebar()) : else : ?>

and

<div class="sidebar-right">
    <ul>
    <?php if ( function_exists('dynamic_sidebar') && dynamic_sidebar()) : else : ?>

Can you tell me if this code is right or what I should change?

Any help is much appreciated ??

GrahamW0009