Newbie Finding it Difficult to Deposit Stellar Backed Asset

Hello, it's easy to understand how to deposit LTC, ETH, XRP, and BTC on the Stellarport.IO site. However, I can't say the same when I want to deposit other assets (specifically, GTN) into the exchange. I don't want to make a mistake and lose my coins. Can you help?

Do I just straight send the stellar-backed asset to my Stellarport.IO public address? My XLM and GTN are in my Stargazer wallet. I have the Stellarport.IO public address. Do I just send directly to that from Stargazer? The website isn't exactly explicit with that. When you choose the option 'receive from another stellar wallet' it goes to the payment page and gives me the feel that I am 'sending' outside Stellarport. I want to send 'in', not 'out'. It's confusing. Or maybe it's my comprehension. Either way, the UX is horrible. :-(