In order to activate and get your skin from FORCE-DROP.COM:

1. Copy the code that you received from G2A after purchase
2. Go to FORCE-DROP.COM and click the button "SIGN IN THROUGH STEAM
3. Save your Steam Trade URL on profile page
4. Enter the code next to the button "Redeem G2A code" and click "Redeem G2A code"
5. Afterwards you will be redirected to the page with the case where you can open it
6. Once you open your case, go to your profile and take your prize , by clicking "Get".
7. Finally, You just have to accept the request to trade in your Steam account

Please note: It is important that your inventory privacy is set to "Public visible" in order to receive purchased skins.