How to access theme editor on Wordpress Free

Hey guys,
I need to add popunder ads to my website, and therefore need to access the theme editor. My site was built with Wordpress Free (so I can't use plugins) and the domain is a free .tk domain. Whenever I access the admin screen, under Appearance, I cannot see the editor option. According to the Internet I need to access some .php file and edit it to see the editor. How do I do that? P.S I have no web hosting: only a domain that forwards to this WP site.

you can find free wordpress plugin
search plugins
https://wordpress.org/plugins/

we do not recommend using WordPress file editor to edit theme files because there is no undo option. Making direct changes to your WordPress theme is also a bad idea. Those changes will disappear when you update your theme. If you are just adding some CSS, then you can add it as custom CSS in WordPress.

phylliss.green said:

we do not recommend using WordPress file editor to edit theme files because there is no undo option. Making direct changes to your WordPress theme is also a bad idea. Those changes will disappear when you update your theme. If you are just adding some CSS, then you can add it as custom CSS in WordPress.

Click to expand...

No: I want to add the adcode for PopMyAds. Is there any alternative way?

spyguyzz said:

you can find free wordpress plugin
search plugins
https://wordpress.org/plugins/

Click to expand...

Yes, but I can't add them without upgrading to Premium (as far as I know). If there is any other way please let me know. Thanks!