How to remove the side bar from certain pages

What theme are you using? Does it have a template with no sidebar? If not, you may need to make one:

https://codex.www.ads-software.com/Stepping_Into_Templates

Be sure you are using a Child Theme for any customization to your theme:

https://codex.www.ads-software.com/Child_Themes

copy past the code form the page.php and make a new file full-width.php end delete the <?php get_sidebar()?> instruction. Go to your page overview in wordpress to quick settings en set the theme of the page you want on full-width.php.

To remove sidebar from a particular page, select ‘Edit’ for the page; now under Page Attribute on the right, select ‘Full Width, no sidebar’ under ‘Template’. Let me know if it works.