How can I redeem this giveaway?

https://www.steamgifts.com/about/faq

If I win a gift, when can I expect to receive it?
Giveaway creators are allowed one week to send the gift after the giveaway has ended. Depending on the type of gift and the giveaway creator, you might receive the gift to the e-mail address you have listed on the account page, a key might be added beside the gift you won, or the giveaway creator might have sent you a friend request on Steam to make the exchange. Please remain patient, and do not contact the giveaway creator during this time. If the gift is not received after one week, you can mark the gift as not received, and attempt to contact the giveaway creator on Steam to follow-up.

Enter the key here https://store.steampowered.com/account/registerkey
or wait the steam gift.

If creator didn't deliver the game after one week, mark it as not received and move on

Maybe they send the key / gift / link to your email?

The creator hasn't been online on SteamGifts in two weeks. He used the site a little and seems like since then he completely forgot about it, including delivering your stuff.
Mark it as not received and move on, or try to contact him on Steam. Nothing else can be done.

Giveaway creator hasn't been online on the site for two weeks, so probably they forgot or can't log in and send the key right now.

I asked why I did not receive any requests or emails or spam.

I did the screenshot -> https://i.imgur.com/YxbTxyS.png

Do I have to mark it as not received?