Since people still don't know how to do it and I have nothing better to do, here's a Step-by-Step guide how to do it to avoid confussion, and also to (hopefully) avoid the "I got banned for no reason" posts that will pop out in the Forums after the event

1. Go to https://scrap.tf/deposit and select the item(s) that you will gift. (They have to be worth at least 1 Ref.) And then click on "Deposit Items". ( https://i.imgur.com/FIRnCGK.png )

2. After you do that, go to https://scrap.tf/santa and click on "Gift Items". ( https://i.imgur.com/nMMMxcN.png ).
Your deposited items will show up ( https://i.imgur.com/OGclf6h.png ).

3. Click on the items and then on "Submit Gift". ( https://i.imgur.com/iuhIJRf.png ) 

4. Click on "View Current Gift" and your Gift will be shown. ( https://i.imgur.com/iyruouc.png )

5. You're Done!


***IF YOU SEE SOMETHING LIKE THIS: https://i.imgur.com/9qf9GCQ.png (Screenshot by -|GBYELO|-) Then IGNORE EVERYTHING! That just means you aren't in the event so you can't send gifts