Hi Kayhlan !
First of all welcome to gothicat world, hope you will enjoy the game ^^
About your question, if you want to create a ''group'' or a clan for your creatures you have to go to ''my creatures'' and click on the ''clan'' button at the top right of the page : ( click to enlarge). If the buttom does not show up, try pressing F5 on your keyboard to refresh the page :
When you've managed to click on the button, click on ''create a clan'' and write down what you want as a name. This will automatically create a group.
If you want to move the creatures to the group, you have to select them and ''move the selected creatures to the clan'' which you can find at the bottom of the page. Press ''ok'' and there you go ^^
Hope it clarifies the situation a bit !
If you have anymore questions feel free to ask.
Efellia