How can I manually edit title and meta descript...

Make sure you have either the WordPress Seo by Yoast plugin or the All in One SEO Pack plugin installed and activated.

1. From the WP admin dashboard, go to Directory -> Listings
2. Click the Fields tab.
3. From the Available Fields panel on the right (or left for RTL languages), click Single Line Text.
4. Enter “meta_title” for Field name.
5. Enter “Meta Title” for Label.
6. Under Visibility Settings, unselect all checkboxes but the Administrator checkbox.
7. Press the Add Field button to save the field.
8. From the Available Fields panel on the right (or left for RTL languages), click Paragraph Text.
9. Enter “meta_description” for Field name.
10. Enter “Meta Description” for Label.
11. Under Visibility Settings, unselect all checkboxes but the Administrator checkbox.
12. Press the Add Field button to save the field.

Now, try editing one of your listings as administrator and you should see two new fields you just created. Enter values for these fields and they will replace the original values that were automatically generated by the plugin.