The process is the same from any wallet you have chosen to use.
The page may change as the site is updated, but the principle is the same.
Simply click the "send" button in your respective wallet.
Once received, it will start earning the following day.
Most people will already have a Bitcoin wallet and some Bitcoin in it from purchase or earnings.
If this is you then skip the next paragraph
You will first need to buy bitcoin in order to purchase USI-Tech products.
There are several factors to consider when choosing a method for buying bitcoin.
Wallets and exchanges are two different things.
A wallet is where you store your bitcoin and send/receive bitcoin.
An exchange is where you actually purchase your bitcoin.
Most all exchanges provide a wallet, but not all wallets offer exchange services.
Coinbase.com, Coinmama.com, Localbitcoins.com CoinWithCard.com are all popular options depending on how fast you want it and if you are willing to pay extra fees for speed and convenience. (This video is courtesy of another business I am in for gold saving.)
Also, you can try this resource: Buying Bitcoins Worldwide