STRAIGHTASADIE:
I get this all the time.
I receive the free 3 ball trial, but can never equip them most of the time.
I have 3 free trial balls now that i cannot equip.
In fact i cannot equip anything, all i have is a driver and a ball.
It states drag your bag here to equip clubs, there are no bags to drag, just a sign saying visit pro shop, when i click on that nothing happens.
Rubbish
Your equipment shows a D, 3W, 3H, irons, 2 wedges, putter and ball. They are equipped.
A stand bag is sold in the Pro Shop as a separate item - it is just for looks and if you buy it, it can be equipped.
You drag any other club or ball in your inventory to the appropriate slot to "equip" it, which means it will be available when you play.
You can only equip one type of ball at a time, which makes it difficult to use up the single ones that we get sometimes.