seo – my page does not appear in the search result (indexed)

I created a website on a double glazed window a week ago. I put it in the Google Search Console and indexed it instantly, and in the search result I found it with the word "پنجره دوجداره" on page 10 and with the word "پنجره upvc" on page 9.

Then, the next day, I created a product page like and related to the double-glazed window page and put the link on the double-glazed window page. Every day I did that.

Now my problem is that every day, after indexing a new page, I searched with the usual keywords and found a new page instead of a double-glazed window. And it disappeared after 10 or 11 hours later.

What could be the problem?