There are multiple ways to do so.

Spot markets (Recommended)
The easiest way to buy a leveraged token is on its spot market.  For instance you can go to the ETHBULL/USD spot market and buy or sell back ETHBULL.  You can find a leveraged token's spot market by going to the tokens page and clicking on the name; or by clicking on the underlying future on the top bar and then on the name of the market.

Convert
You can also buy or sell leveraged tokens directly from your wallet page using the 'CONVERT' function.  If you find a token and click 'CONVERT' on the right hand side of the screen, you'll see a dialog box in which you can easily turn any of your coins on AscendEX into the leveraged token.
Creation/Redemption
Finally, you can create or redeem leveraged tokens.  This is not recommended unless you have read through all of the documentation on leveraged tokens.  Creating or redeeming leveraged tokens will have market impact and you won't know what price you ultimately get until after you've created or redeemed.  We recommend using the spot markets instead.

You can create or redeem a leveraged token by going to the tokens page and clicking 'more info'.  If you create $10,000 of ETHBULL, this will send a market order to buy $30,000 of ETH-PERP, calculate the price paid, and then charge you that amount of money; it'll then credit your account with the corresponding amount of ETHBULL.

Disclaimers

  1. None of this is investment advice.
  2. Much of the below analysis ignores any difference between futures and spot prices, and ignores the effects of fees.
  3. Leveraged tokens greatly reduce the risk of liquidation but cannot make it fully impossible; if markets instantaneously gap down 50%, there is nothing that can stop a +3x leveraged position from getting liquidated.
  4. Leveraged tokens, like the rest of AscendEX, are not being offered to US users.