Ok - first stop antivirus - choose a good one - I wont recommend as everybody will start piping in with their favourites.
Essentials - Adobe Reader and Flash Player - only download those from the real website
http://www.adobe.com/uk/#
To play videos divx
http://www.divx.com/
When installing the above dont take any unwanted extras.
Consider a different browser i personally dont rate Edge.
keep tapping your Windows update button as there will already be updates available for Win 10. Dont forget to add your printer there may be a new Win 10 driver for it.