A set of 4 caches (The Traditional, The Multi, The Puzzle and The Wherigo) which we are making available to all members, placed to help and encourage those who are new to our wonderful hobby. Unfortunately only The Traditional is available to basic members but if you are a basic member why not try a month’s free premium membership to see if its for you!
If you are planning to find them all in one day we recommend you start with The Multi.
A traditional cache is the simplest type of Geocache, a container is placed at the posted coordinates.
There are lots of different container types and sizes. Take a look at Geocaching.com help centre "Cache container examples" for some ideas or do an internet search to see some of the more unusual ones.
https://www.geocaching.com/help/index.php?pg=kb.chapter&id=128&pgid=75#polypropylene
Check out the size at the top of the cache description. The important thing is to SIGN THE LOG to claim a find. Some containers (like this one) will be too small to hold a pen so always bring your own. This one is a Bison® tube in a wooden hole.
Also important is the D/T rating. The D is for difficulty (This is a 1 rating so hopefully easy to find 
) The T is for terrain (This is rated 2 because of the uneven ground and because sometimes it may be muddy/slippy)
Good luck and happy caching!