In order to activate and get your skin from DropLand.net:

• Copy the code that you got from G2A after purchase
• Go to DROPLAND.NET and click the button "SIGN IN THROUGH STEAM"
• Save your Steam Trade URL on profile page
• Enter the code next to the button "redeem code from g2a" and click "redeem code from g2a"
• Afterwards you will be redirected to the page with case, where you can open your case
• Once you open your case, go to your profile and take your prize , by clicking "Get".

Finally, You just have to accept the request to trade in your Steam account
Please note: to receive your skins, your inventory must be open public account should have no currency restrictions.