Salam,

Don't worry about it, set a description as good as you can and create keywords that cover the site or page if it is totally different from the site.

Let X5 take care of the rest, that's why you have it and it will work for you, trust it, fine tune later.

You can check some advice that x5 gives you by checking step5 , project analysis.

You have three filters on op,  see that there are no error's this needs to be zero, check the alerts, don't be afraid if there are some left x5 will do it's trick anyway, but it gives you a good idea on items to check. The alerts do not need to be adjusted to zero but checking them does not hurt.

Also there is an information filter, this is the least importand button.

Give yourself also some time even with errors you can upload your site and most basics for SEO will be automaticly set.