HOW TO UPGRADE MEMORY on HP ALL-IN-ONE DESKTOP PC

HP Pavillion 23" TOUCH FULL HD IPS LED,  AMD QUAD-CORE  4GB RAM/1TB HDD ALL-IN-ONE WINDOWS 10 Desktop PC w/Software. (ITEM # 469-586.)

  In the Specs, Under MEMORY it States: 4GB DDR3L (Expandable to 16GB).

What is the BEST WAY to ACHIEVE THIS & still Purchase it from HSN ??

      NOTE: I’ve already looked on HP website, Configure section & saw How they do it. However, Prefer to stick with HSN.