This function in the HEAT p2p server wallet, can I trade directly in the P2P wallet? but if P2P happens what will be the currency of exchange? BTC, ETH? Thanks 
You can trade assets on HEAT blockchain directly p2p.The only native cryptocurrency asset on the HEAT blockchain is the HEAT coin.
Any other assets are tokens, which you need to obtain by transferring your genuine crypto to a gateway that converts it to HEAT asset.
BTC gateway is seamlessly integrated to the Heatwallet UI and accessible by clicking the DEPOSIT BTC button on relevant DEX screens.
To trade with BTC you may have stored on your Bitcoin Heatwallet, or any other Bitcoin wallet, you need to first transfer these cryptos from your Bitcoin (Heat)wallet to the HEAT assets by clicking on the DEPOSIT BTC button.
And we wonder why crypto has problems being adapted mainstream. Ive been in crypto for over 1,5 years.. and Ive no damn Idea what you just said. Wtf is a heatwallet bitcoin? So for me to sell my btc that is on i.e. binance, i have to transfer it to heatwallet btc, then trade into heat, then trade heat into something else? Ever heard of usability lol (no FUD, but sarcasm intended..)
Who is ever going to use such a complicated thing..
I have to admit the ui is pretty alright. The main thing about this scam coin is that it is run by amateurs, has a vry bad reputation and most importantly is based on trust(trust the token issuer to pay you out your coins) and pure will of the devs(since it is not open sourced) and not on crypto. The devs even control the fee price.... This is not a decentralized blockchain. Why would you use heat instead of eth? Why would you even use heat instead of a mysql database driven central exchange?